With a half-decent graphics program (Paint Shop Pro, Photoshop, etc) and some creativity.
"does the banner need to include motion?"
Only if you want it to, and that requires a more advanced program, usually.
The big question is what you want to make a banner for. Suit what you're making to what you're using it for. If it's a signature image, something static and simple is probably best. If you're making it for your faction, then you might want to make it animated, and a bit flashier than a signature image.
"May the Grace of Ara go with you, and His Vengeance be wrought upon your enemies."