But if you live in Charlotte, NC, we have good news! AT&T just started rolling out its 3G MicroCell in the Charlotte market, with other areas presumably to follow.
This is how it works: you buy a 3G MicroCell adapter which connects to your DSL/cable router (or presumably your Ethernet connection at work). This adapter increases the signal strength of your 3G phone by allowing you to make calls using the Internet connection. So, you get full bars of service in your home, regardless of your cell-tower proximity. Up to four devices can use the MicroCell at one time.
Additionally, your data connections will be faster (although we don't know how it would be any different than just using the WiFi for data access on its own). The MicroCell is $150, and service is free (at least in the Charlotte trial), though if you want to make unlimited calls from your MicroCell, you'll need to pay another $20 per month.
The whole solution is pretty similar to T-Mobile's Hotspot@Home system (although that will work with any WiFi router, provided your phone supports WiFi) and is similar to offerings from Sprint and Verizon (although neither Sprint or Verizon offer 3G data speeds).