Twitter is a web 2.0 website where people post what they are doing right now. Posts come from cell phones, IM, or directly into the website from the web. Not my cup of tea, but it seems to have a large following.
MiTreo.com has released a Palm application so you can post straight to Twitter from your phone using this application.
It’s also worth noting this is the first application I’ve seen draw a wide following that was first developed in Spanish. MiTreo has several programs on the site that started in Spanish or have been ported. So native Spanish speakers should give them a visit.