[DJZMC]

Is there a way that I can have my iMac G5 hooked up to wired internet and have my Powerbook access the internet through airport from my iMac? I have them networked, but I can't figure out the rest. Thanks.

[d00d]

Yes, you can use internet sharing, but due to the way OS X's built in firewall works, you need to poke holes it in it. It's far cheaper and easier to simply buy a wireless router. You won't need to keep the iMac on either, which is going to cost you money and hassle in the long run. The router will have better range and also offer protection to both computers.
Get a router, it's just a better all around solution.