Are you looking for a modem that can be upgraded?  Do you dislike the bulky-ness of the Handspring Modem?  Then check out the Wristband Thincom by Card Access, a standard size Springboard module that sets the standard for future Springboard modules.

Physical Specifications

The name "Thincom" should give you a good hint as to the Springboard module's size.  This 33.6K modem, when not in use, is a standard-size module that stays out of the way.  When you're ready to use the Thincom, plug in one end of the 6' dongle cable into the module and the other end into an analog RJ-11 jack.  The Thincom has special power-saving features that draw less than 50mA when connected -- half the amount that Springboard modules have available to them.  The Thincom, which is only available in graphite, has a light green label that doesn't detract from the look of the Visor.

Upon insertion, the Thincom chirps and sounds like you just inserted a PC Card into your Visor -- however, you can disable this in Thincom Setup.  And, through that insertion, you have just setup the Thincom -- it has the most full-featured setup of any Springboard module to date.  Everything from how to connect the modem to quick access to your ISP settings is in the Thincom Setup.  You can also specify speaker volume and whether to use the Status Screen or not.  Every Springboard module should have a setup application as good as the Thincom.