I highly recommend against attempting to convert from PC to MAC. The PC version of the program is ten times better not even considering all the crashes you will get with the MAC version. You also cannot convert any of your payroll data. Keep the old PC and just use it for accounting...

Remember it is very easy to network with windoz machines now and all your excel data is interchangeable.

Here is part of the QuickBooks Pro 2005 for Mac online help on conversion - please refer to this and the User's Guide, as well as the support area of quickbooks.com for additional information:

Converting a QuickBooks file from Windows to Mac

QuickBooks for Mac can convert a file created with:

QuickBooks Basic Edition 2004 or 2005 for Windows
QuickBooks Pro Edition 2004 or 2005 for Windows
QuickBooks Premier Edition 2004 or 2005 for Windows
QuickBooks Premier Accountant Edition 2004 or 2005 for Windows

To convert a QuickBooks file from Windows to Mac:

1 Copy your QuickBooks for Windows data file, either .qbw or .qbb, from your PC to your Mac.
2 In QuickBooks Pro 2005 for Mac, choose either File > Open Company to open the .qbw file, or File > Restore > From QuickBooks for Windows to restore the .qbb file.
3 Follow the onscreen instructions for opening the file.

Depending on the size of your data file, the conversion process can take up to ten minutes.

Data that is and isn't converted from QuickBooks for Windows to QuickBooks for Mac

Although Intuit has used reasonable efforts to include all features affected, Intuit disclaims that all features are included in these lists. Be sure to compare the newly-converted data with the original data to learn what data was not converted.

Data that IS converted
Account list (chart of accounts)
Customer list
Vendor list (notes will not be converted)
Item list
Terms list
Shipping via list
Customer type list
Vendor type list
Employee list (notes will not be converted)
To do list (alerts will not be converted)
Other names list (without notes)
Job types list
Payment method list
Customer message list
Classes
Reminders (alerts will not be converted)
Links between pay items and other items
Custom field definitions
Transactions and their links:
- Invoices
- Bills
- Deposits
- Payments
- Estimates
- Sales receipts
- Transfers (will be shown as a journal entry)
Memorized transactions
Memorized reports (in alphabetical order, without groups)
History of QuickBooks versions used with the data file
Transaction statistics
1099 categories
Notes
Audit trail
Preferences
- Company name and address
- Which features are enabled
Time and activity records
Budgets
Reconcile
Address book data
Income and expense tracking by class (available in QuickBooks Pro 2005 for Mac using Profit & Loss by Class reports)
Job costing data (available in QuickBooks Pro 2005 for Mac using Job Profitability reports)
File passwords

Data that ISN'T converted
Some features and data will NOT be converted from PC to Mac, including (but not necessarily limited to) the following:

Intuit integrated payroll and payroll item lists (QuickBooks Pro 2005 for Mac uses Aatrix Top Pay for payroll services)
Online banking transactions that have not been accepted into a register (transactions that have been accepted will appear as payments, deposits, and transfers with associated links)
Customized settings for forms like invoices, estimates, statements, and purchase orders (forms can be customized in QuickBooks Pro 2005 for Mac)
Multi-user data, such as sales representative information
Business planning, expert analysis, and business optimization tools
Customized price levels
Integration with third party applications, including Microsoft Word, Outlook, and ACT!
Merchant account services
Multiple estimates per job (QuickBooks Pro 2005 for Mac supports a single estimate per job)
Sales order and back order tracking (available only in Premier versions of QuickBooks for Windows)
Assembly items (available only in Premier versions of QuickBooks for Windows) will be converted into regular non-inventory part items
Transaction type "transfer" (will convert into a journal entry)
Transaction type "EFP payroll" (will convert into a payroll liability check)
Workers comp list
Vehicle list
Fixed asset item list
New columns added to lists
Loan manager
Edit/Void Paycheck
Print 1096
Credit check
QuickBooks Online Billing
Sales tax code list

Unsupported reports
The following preset reports are currently not supported by QuickBooks Pro 2005 for Mac. You can, however, create many of these reports using the customization, filtering, and memorization features in QuickBooks Pro 2005 for Mac.

Profit & Loss Unclassified
Job Progress Invoices vs. Estimates
Open Purchase Orders by Job
Sales Tax Revenue Summary
Pending Builds
Income Tax Preparation
Profit & Loss Budget Performance
Estimates by Job
Reconciliation Discrepancy
Previous Reconciliations
Voided/Deleted Transactions (available only in Premier versions of QuickBooks for Windows)
Voided/Deleted Transactions History (available only in Premier versions of QuickBooks for Windows)
Closing Date Exception (available only in Premier versions of QuickBooks for Windows)
Open Sales Orders by Customers (available only in Premier versions of QuickBooks for Windows)
Open Sales Orders by Item (available only in Premier versions of QuickBooks for Windows)
Adjusted Trial Balance (available only in Premier versions of QuickBooks for Windows)
Adjusting Journal Entries (available only in Premier versions of QuickBooks for Windows)
Forecast Overview (available only in Premier versions of QuickBooks for Windows)
Forecast vs. Actual (available only in Premier versions of QuickBooks for Windows)
All payroll reports
All mileage reports
All list reports