Quasi is a very easy-to-use, step-by-step application. It starts by asking you which files you want to group together. You can select multiple files at once and later reorder them. When you go to combine the files, you're shown the final file to see if you like it or not. If you do, all you have to do is save it (and, optionally, apply a Quartz filter). If not, the file is automatically deleted off your hard drive.
Quasi is available for US$9.99 .