Already been down that road - I owned a C500.
If you are in the house why not just use bluetooth access instead of WiFi to access the web? I do it all the time with my C550. No paying Orange for the data charges and it's much faster than GPRS
And the reason...?
Because range is naff - so for "round the house" read "sitting near to your pc" (which kind of defeats the whole object yeah?). I exagerate slightly, but you get my point.
Also, PC needs to be on...
And finally, speed...
I have 10Mb Broadband...
So using BT, the bottleneck of BT is 725Kb (theoretic max).
Using wi-fi, with a limit of 11Mbps, then my browsing speed is then a (theoretic, but still MUCH MUCH faster), 10Mb itself.
And having a pre-n belkin router, the speed IS really near that, the range is unbelievable - out in the garden, on the loo, next door at sisters etc, and the pre-n router works mixed mode without slowing down to the lowest standard (802.11b)
Those arguments, make "just use BT instead" a none-starter from the off, where wi-fi is concerned.