Have you heard about Twitterkeys? It’s a site that puts together a list of special characters that you can just copy and paste and put into a Twitter post.
Where as they are marketing to Twitter, these symbols work great for Plurk, ReJaw, Facebook, email or whatever you want to use them with.
Twitterkeys offers lots of different symbols from hearts to stars and even a snowman. I think there are about 200 symbols to choose from.
Check them out as it may come in handy.