I was continually frustrated with SMB in OS X 10.2. It is extremely unreliable, crashes the Finder, and times out for large files. So, I found the simple solution, both of which I think also work in 10.1: use FTP Access or Personal Web Sharing (Apache). In the Sharing system prefs pane, check one of them.
If you use Personal Web Sharing, put the files you want to transfer in ~/Sites, then on the Windows machine, go to http://ip/~shortusername/ to access your files. If you want to do bidirectional transfers (i.e., from Windows to Mac and vice versa), use FTP Access. On the Windows machine, connect to the Mac using your short username and password.
Using either method, you can only browse your home directory, but that's where you should be storing documents and such anyway. If you're concerned about security, use something like Norton Personal Firewall (I use it on my iBook because I use multiple wireless networks).
I'm now happily transferring files at 600 KB/sec over Airport to Windows after struggling for weeks with Samba!
Mac OS X Hints
http://hints.macworld.com/article.php?story=20021016070543401