In the Signature Options you will see an icon of the Earth with a link. Just click that and it should give you the option of using URL tags before/after your link.
2014 Conventions :
Katsucon (Washington, DC) - Megacon (FL) - Colossalcon (OH)
Upcoming costumes : NiGHTS from NiGHTS: Journey of Dreams, Princess Kraehe (anime) from Princess Tutu, and Zidane Tribal from FFIX!