Thanks for your replies. Based on what you're saying, iamdrumming and chimpanzee, sounds like I'm out of luck. That was my main reason for wanting the browsing plan. Unless your suggestion, Jon2010, of setting it up as an activesync account works -- only problem is that I have no idea how to do that. Are you able to give me a step-by-step so I can give it a shot?
Thnx

Most ISPs these days have webmail access to your email account. You can use the browser to do email that way. Yahoo and Gmail work fine through the browser. If your ISP doesn't have webmail you need to change ISPs, that's kind of standard these days.

best alternative is to get a gmail then retrieve your ISP email via IMAP and retrieve gmail via activesync/exchange, which works over UMB.

Or you could setup a gmail/hotmail account to check your other email account if possible, then set it up as and activesync/exchange if possible.

In fact on iphone 4, even yahoo would not work using the builtin client, as it is a convoluted IMAP. On Android though, it would work as the yahoo app there use http/https(i.e. web protocol) to access the service.