Character Portraits are optional, but can be quite useful and inspriarational.
But not everyone is a born artist. So for those who have yet to develop their skills, looking to make a draft before comissioning an artist, or simply want to toy around with some ideas; here are some resources that might help. (Feel free to add some yourself in this thread)
Heromachine - A classic old school tool
ChibiMaker by Gen8 - A tool using the "Chibi"-style
Hero Forge - A site where you can create character miniatures and have them printed and shipped to you, but the miniature image can also be saved.
Rinmaru's Mega Fantasy Avatar Creator - A Bust Portrait tool with a little more detail
Dolldivine.com - A site with a lot of "Paper doll"-style Dress-up games that can be utilized for portrait creation.
GIMP - A freeware alternative to Photoshop to touch up on any portraits you create.