Well, here’s an interesting one, a cell phone Java based trojan. It’s not a huge threat at the moment (requires a lot of user interaction), but good to know about anyway:
This just means that like your normal computer, you should not open files that you don’t know about or trust 100%. It will only affect phones with Java, and only if you let it (i.e., you click on the link and say yes to it sending SMS messages).
What’s more important are the possibilities, this isn’t as much a failure of technology as a failure of user education if this goes anywhere. Get used to this, it’s the future. 🙁