so when you press it it just makes it faster...but it said something about matching a cd or something in the manuel someone hit me up with details

Man, you have to tap the button in the time of the song you are going to sample so you will get he right bpm. You can do this too in the pattern mode so your patterns wil play in the same bpm of the external source.
Let's see if I can explain it better, if you want to sample something:
1. put some song to play via the external source
2. press rec and select the pad you want
3. press the Time/bpm buton
4. start to count the beats of the mesaure of the song "1-2-3-4-1-2-3-4" and press the tap button as you count
5. so you will have the right bpm.

If you want to sincronize a pattern with a external source just follow the steps 3 and 4.
An by the way, it doesn't just make it go faster, it all dependes the rythm you are tapping.

Sorry about my english. I hope I had answer your question.

That's a perfect explanation.

yeah man thanks so much!

you're welcome!:)
Tap tempo is a really usefull tool! And nowadays there is a lot of machines that has this features. It's good too if you play with a live band.

i trust the bpm counter, but i still tap to samples and loops. its pretty usefull for getting an idea what tempo the record is , then adjust the tempo before sampling, .