Currently in beta and taking beta test requests at the moment, Skyfire is a new proxy-based web browser for the Windows Mobile platform. Its claims to offer the full web on the run seem to be substantiated by this video which showcases some impressive content which would normally only be available on a desktop browser.
In concept this seems very close to the aging (if not dead) Thunderhawk browser, which was popular around the time of Windows Mobile 2002/3. This suffered from an expensive subscription fee, necessary to support the bandwidth being pumped through the proxy server where all the fancy conversion from web page to Thunderhawk image was performed.
Skyfire looks, on the face of it anyway, to be a step forward from Thunderhawk, if not quite up to the performance of the amazing Picsel Browser. Once the Skyfire guys bring this out of beta it will be interesting to see how well it performs and whether they can keep it free.