Tell me about the iPod touch?

Its old and limited in what it can run. Go to the Apple site and check it out, they show what each device can do.

IPhone=Phone, hence the name
iPod=Media player that can do almost everything that the iPhone can do, except cell related features, such as calling or sending text messages, or using GPS.
iPad, similar to the iPod, except much larger. If you get a 3G/4G version, it can connect to a carrier and get Internet wherever there's service.

I highly, highly, highly recommend that you don't get neither of those devices. The iPod touch 2 is extremely obsolete. There hasn't been any iOS updates in about 5 years, nor will there ever be anymore. That last iOS version compatible with that device is iOS 4.2.1, and VERY few apps still support that ancient firmware.

The iPod touch 3 goes up to iOS 5.1.1, which came out 3 years ago. This iPod touch has been discontinued for 5 years. Minecraft Pocket Edition will work on this iPod touch, but how well, I don't know.

I strongly urge you to get at the very least, an iPod touch 4. Preferably a 5 or 6.