Sprint's Data Card doesn't fit my Inspiron E1705 -- HELP!

You'll need to wait a few months. ExpressCard-format CDMA cards aren't on the market yet, but there are a few slated to become available in April or May I believe. ExpressCard is very new, but the fact that numerous manufacturers (Most of the major players in fact, such as Dell, Apple and I believe Toshiba) have moved entirely to ExpressCard is going to force things to speed up just like the USB-only iMac caused an explosion of USB peripherals onto the market.

You may also want to reconsider using the Data Card.  If you get a Samsung A920 from Sprint, you can get a Phone As Modem (PAM) plan for $49.99/month (unlimited usage) that will allow you to use the phone as your connection to the cell towers through the provided USB Cable.  According to their site, the PAM can be as fast as broadband speeds.  What that means I can't be 100% sure because I've never used it, but I'm sure it won't be horribly slow like dial-up. 

The phone is pretty cool.  I have one, but I'm not in a work environment where I would use the PAM plan and it's not something I could see me spending for.  However, the built  in bluetooth capabilities and speed for the Sprint Power Vision Network is pretty nice at only $25 a month ($10 more than standard vision).