I have not tried it myself, and I am a bit worried about the potential security issues (ie, the folks who run this service will be able to read all your emails), but...
I occasionally use mail2web on my phone, and so far I've had no problems. The mailbox can be a bit of a struggle to navigate, but that just means that it takes time to do.
If you need to check your mail on your phone, its a fairly good way to do it.