Hiya Starwars42097,
A friendly tip;
Much of the stuff a new member might wonder about, has been discussed.. sometmes many times.
If you use the forum search option, with the correct search parameters, you can find a lot about.. well, a lot.
Anyway, you'd basically have to make it first, with a program like paint, photoshop, paintshop pro, etc..
Then, you'd have to upload it somewhere, so it's hosted on the net and can be used. Most people use imagehosting sites, like photobucket, tinypic, imageshack, and such.
If you'd like help on the creation front, our resident signature wizard is TJK, who often helps people out by making them nice sigs. You can contact him (PM) and see if he has the time to make you something nice.
Regards,
Fred
