You can try this but it did not work for me and I ended up with slower 3g speeds.
I do recommend you write down your current settings before you do this just in case you need to revert:
1. Get your MSL, There are many ways, call Sprint, Download the app MSL Reader from the market, CDMA workshop
2. After you have your MSL go to your phone and type ##3282#
3. Click Edit Mode
4. Click Advanced
5. Scroll down to HTTP PD Proxy Port & HTTP PD Proxy Address
6. Change HTTP PD Proxy Port to 0 (zero)
7. Change HTTP PD Proxy Address to 0.0.0.0
8. Go enjoy Downloads and a .20-.60 mbps increase in 3G speeds!
Got this from this
thread.