If you want an automated satalite tracker to transmit your location at regular intervals and update a website map or just let family know where you are, like the SPOT I don't think there's much else on the market.
But one solution I think may work quite well is to forget about using sat technology at all and use a normal cellphone. Reception is good all the way down the east coast as most people use them rather than landlines and if you use locally bought sim cards it may even work out cheaper.
You'd have to be a bit more hands on than a SPOT unit though. I'd look into setting something up via twitter.
1. You check your long/lat on your gps.
2. Send twitter an sms with your location.
3. Location is published on twitter for everyone to see.
With the help of a slightly savvy programmer you could then have a script set up to:
4. Check your twitter stream for location updates.
5. Take the location and create a google map link.
6. Publish that link back onto twitter/facebook/blog etc
7. Add the location to a database as a new waypoint.
8. The updated database creates an up-to-date map on your website.
Or just have a friend read your text message and do it all manually for you!
Or maybe give these web tools a try:
Plazes
Plazes - Right Plaze, Right Time
FireEagle
Fire Eagle
Google Latitude
Google Latitude
Maybe not replacements for SPOTs "HELP!" feature, but if you just want people to know where you are it can work quite easily.