Chocobo King: Most, if not all, graphic editing programs have a thing called a Text Tool. Find it on your toolbar in the program (Photoshop/Paint Shop/GIMP/Paint/Whatever), click it and experiment. You shall have your text.
For seeing about how large the filesize is and making sure that it is alright for Eyes on Final Fantay's fora, there is usually an image optimizer in, again, most graphic editing programs. I'll attach a screenshot of where it can be located in the program I use, Paint Shop Pro 9. All images in signatures must total up to be 50KB or less, so keep that in mind. If you are talking about dimensions, then make sure your dimensions are 550 pixels or less in width and 250 pixels or less in height.
As for uploading, you may want to check out [Image Bucket] or another online service that, for free, hosts images for people. You will have to make a register, but that is hardly a bad thing for free image hosting, right? Anyways, most image hosting services have really easy tools for uploading, so after that, it should be no issue.
