As some of you might be having a doubt whether it is possible to access GMail or any other popular email account from Blackberry without BIS or BlackBerry services.
Yes, it is possible to acess Gmail, MSN, Yahoo or any other email from BlackBerry using a Wi-Fi connection.
There very few applications of which I found LogicMail to be reasonably good. It is an opensource BlackBerry application (ie., written only for BlackBerry) and is advertisement free.
It works like a gem in my blackberry 9900, which is running on BlackBerry OS 7.1. In this application you can configure any number of email accounts. POP and IMAP are the supported protocols.
Your copy can be downloaded from the official website www.logicmail.org