Here is another iChat tip. This one for texting.
When texting, you can make the text in your chats bold or italic or change your font or font color.
For bold press ⌘B and for italic press ⌘I. To change fonts choose Format → Show Fonts and for colors choose Format → Show Colors. If you use a far out font that your chat buddy doesn’t have installed on their machine, they will see something different.