Anyone know any good photoshop cs3 brushes I can use?

There are hundreds of great photoshop brushes. The version doesn't usually matter because most are made for Version 7.0+ and if they end in .abr they should work with those versions.

Try visiting sites like:

www.deviantart.com

Or look around for forums on IPB or vBulletin providers because most big graphic forums with great resources end up there.