There is no way to view mail to your BlackBerry email address directly on a computer. The best you can do is forward it to an email address on your computer and view it there.
I usually save the attachment to my media card and then connect my berry to my computer and pull the attachment from it.
Posted from my CrackBerry at wapforums.crackberry.com
Posted from my CrackBerry at wapforums.crackberry.com