I was searching about playing MIDI in the mobile, but I not found much information. So, Android has a MIDI synthesizer? Varies according to the model?
Searching the Market for "Midi" shows quite a few apps that have some level of midi functionality. If you're looking for a full-fledged midi app such as you'd find on a PC or Mac, you will probably be disappointed due to the small screen and limited hardware interfacing capability of most Android devices, but if you are looking to experiment with midi functionality, one or more of these apps should do the job.