Yes, you may upload more than one application! When uploading your application try to choose the most suitable category available. If you feel that you must upload to multiple categories you may do so. For now, you are only allowed to select a maximum of two categories for each individual application.
Remember that you can always tag your applications with keywords to make them easier to search for. A search function is available on the SlideME site, and will also be on SAM, our mobile client application.