What kind of programs would you recommend, where you can design your level in tiles and is easy to use and understand?
Off the top of my head, these are some that I have found useful:
Tiled has been my favorite one so far, specially because there's a TMX importer plugin for C2 around here.
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I am using a free 3d application called Blender. Great for nice 3d looking tiles, and easy animated sprites.
Neotextureedit is handy for making seamless tiles too.