Update 3: ZodTTD, developer of several well-known emulators, recently met a similar fate as yongzh - both his Market account and his apps were removed. Today, he decided to clarify a few things in a blog post, noting that the removal of the apps was not due to an open source violation but rather came as a result of a trademark infringement letter from Sony to Google concerning PSX4Droid's icon.
Replica Island (Free)
Replica Island is a great, retro game that will keep you entertained for hours. Not only is it available for every device running Android 1.5 and above, but it’s also free.
Guiding your Android through all 40 levels, you must find a mysterious object called The Source in the middle of an island which is protected by all sorts of strange creatures that you must defeat before the Rokudou Corporation beats you to it!