Works Great!!  Thanks for the Post.  :)

I don't know DynAdvance, nor this version of Gmail Notifier yet, but the previous version the Gmail Notifier was very simple, plus it's free.

Although, according to the DynAdvance web page, it supports Gmail, Hotmail, Yahoo! Mail, MSN, POP3 and IMAP, so it's more of an all-in-one checker, but it's not free.

I personally like the Gmail checker built into the experimental version of Googlebar for Firefox.

http://googlebar.mozdev.org/