I lifted this (my) post from a previous thread.
-Subscribe to Sprint's Hotspot service at $30.00 per month. This will allow you to connect via Wi-Fi 802.11 up to six devices to the Sprint network. It works pretty well, but don't expect to see the same tower-to-device speeds on your laptop or P.C. 50% through-speeds is about average.
-Easytether download from the Market. There is a free version that offers connection to HTTP servers only (non-secure) It is very fast, showing 100% through-speeds. The paid version (one time charge of $10.00) allows unrestricted access to all servers (HTTP & HTTPS).
-PdaNet download from the market. Same as above but the one time charge is $30.00. It also offers Wi-Fi, Bluetooth, and wired (USB) connections. It is faster than Sprint's Hotspot, but not as fast as Easytether.
-Root your phone and install Wireless Tether. It is free, has no restrictions, is faster than Sprint's Hotspot, but slower than Easytether.
I use Wireless Tether for casual surfing and Easytether for streaming Netflix to my television. The difference in speed is the difference between watching Netflix in standard definition or Netflix in H.D.