Third the cradlepoint. It gives you the ability to set up a hotspot anywhere you have a cellular signal. That's KILLER.
The router accepts USB evdo modems (e.g. the 595U from Sprint or Verizon) or hard wire internet and turns it into a wireless signal.
However, if you just want to pull the phone out for a short web session than using a wireless modem to a router is a bit kludgy and you'd be happier with a data plan for the phone regardless of the download speeds. I have a Tmobile data for my Palm 750 and Sprint broadband for the 'puter. I am currently dsl and cable internet free!
http://3gstore.com/ gives the best service for the cradlepoint.
Jim