Battery powered Teensy 3.0.

[naps250]

Hello all,
I am new to this forum as well as to the electronics.
For starters I am going to tell you what I have in mind as my project.
I have a CM Storm Switch Tester which is this little thing: http://goo.gl/uRMm2L
I have a Teensy 3.0 on the way which I plan to hook up to the keys and use the board as a normal keyboard.
If that works out I will get a blutooth module ( probably this one http://goo.gl/iZVmP9 ) and go wireless and here are my questions/problems to you guys.
I read on a similar thread that you can use batteries to power the Teensy. Do I need to connect the power to the Teensy USB port pins or to the GND and Vin pins of the Teensy itself?
The space for the battery is very small so I am open to suggestions about what battery/ies to use.
Will this be sufficient to power everything? http://www.adafruit.com/products/1570
Finally do you think it would be good to put a power switch to preserve power?

I am sorry for these simple questions but I have no clue. I did a search before posting but I found only one thread with not enough information.
Hope I haven't forgotten an important detail and thanks in advance for your help and patience.

[Vignesh]

Hi Naps250,
I too am new here and this is my first post. Having said that..
What I understand is, you can power MK20DX... by connecting the battery to the 3.3v terminal/pin. Do look at Datasheet sec 3.9.1.2.1.
But, I am not sure what happens if you insert a USB cable while the battery is present, as VDD and VOUT33 are connected together.
Regards,
Vignesh