Having trouble using gmail as your main client on OS X due to lack of support for the mailto: protocol?  In case you are not sure what the mailto protocol is, it’s simply a tag used in HTML that tells your default mail client to open, compose a new message and inserts the email address to.  gmailto is a new application that intercepts these requests and uses gmail as the default mail client.

This build requires Snow Leopard to work correctly.  If you need more information click here.