We are developing a data compression and optimisation service for Windows Mobile devices that will compress web traffic (http) and e-mail (pop/smtp). You will typically get 3-4 times compression, therefore use only 1/3 to 1/4 the amount of data - i.e. savings on mobile network/cellular data. Compression also applies to basic MS Office files (as web download or as e-mail attachment), and PDF files in the near future. For connections up to 500kbps you will also see significant performance increase, i.e. for GPRS/EDGE/3G/CDMA 1X and EV-DO. It would not matter which mobile network operator you use, or if you change, or how else you get on the internet, you will still be able to use the service.
There is a client to load on your Pocket PC. We have done extensive development to ensure that there is no impact on battery life of the mobile device even where the mobile data session remains open.
Unlike other offerings already on the market this solution is transparent and you continue to use whatever browser or e-mail client you want.
I'd appreciate any feedback (via this forum) as to whether this service interests you, other features/data you might want supported, and whether you would be prepared to pay a (small) monthly or quarterly charge?