Thanks for the pm, for some reason since I have downloaded GIMP my computer has started running awfully slow, any reason why?
You downloaded it from the official website, right?
Well, I have been using Gimp for almost 6 years now, and I must say: if you're aiming to real business, don't even touch it. Don't get me wrong, Gimp is amazing, but if you get too used to it, you will find yourself stuck between being good with Gimp and being noob in photoshop.
This is happening to me now, I want to improve my skills by using a more "complex" software, but simply can't find enough motivation to start learning everything again, since I'm too used with Gimp (and have no time to learn Photoshop because I'm working on paid jobs with Gimp all the time). This situation pretty much sucks, so I really reccomend you to use Photoshop.
Oh, Photoshop also has a lot more resources to explore, and you can find tutorials everywhere. Now, if you're going to make 3D signatures, like everyone makes here in Sythe, use Cinema 4D to make the text and effects, and then Photoshop to make the actual editing.
Hope my advice helps. =)