I want to take a picture with a Canon S3, and blow it up to 20x30. Is that possible? The photo will be in excellent light, will be at the full 6 megapixel resolution, and the quality will be at the minimum compression. I only want to blow up this one picture, so there's no way I'm getting a DSLR just to take this picture, lol.

What program(s) should I use to make sure the picture looks good once blown up? How exactly do I do it? And is there somewhere that I can take the picture (possibly an online place?), and have them print out the picture, and frame it? I've never done this before, as you can see.