This Page by Mark Lyon is full of useful GMail tools. Including importer, exporters and migrators, as well as POP3 access. Looks like a must have for GMail users.
Update: Get the GMail Helper direct from Google. It adds system tray notification and resolution of mailto links to most any Microsoft Windows system. No official support that I know of for Mac or Linux yet. I also hear that some of those unofficial tools from the previous link are being blocked by Google.
pls send me gmail invitations
pls send me
gmail inv
Check out gmail.afraid.org for all your Gmail invite needs. I just donated a lot, and they have thousands in the spool already.