See the link above the forum name 'Control Panel'? Go there. In the 'Your profile' section is the option 'Edit Signature'
The edit box is a little broken, it only shows half a line, so type the sig in notepad and copy-paste it there.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability