Go to your My Account/Your Characters/Set Up Image Signature.
Once you're done with the process there will be a ffxisig tag that you can copy and paste into your signature.
The tag will be in the form of [ffxisig]XXXXXX[/ffxisig] where XXXXXX is your sig's number.
And welcome to Premium!
Edited, Oct 21st 2007 9:39am by Jella