Dear ravelar,
The tactile switch PCB footprint (and electrical model) should be the same as a standard 12mm by 12mm tactile switch.
You can find these at almost every electronics retailer online.
Here's one from Tayda electronics.
http://www.taydaelectronics.com/electromechanical/switches-key-pad/tact-switch/tact-switch-12-12mm-4-3mm-through-hole-spst-no.html Now, the only problem is desoldering it. In order to desolder a part from a multi-layer board with plated-through holes, you have to have a constant vacuum desoldering station. Usually, the EE shop in a university will be more than happy to do this for you, but you should not attempt this yourself (unless you have the tools and know how to do it ;) ). (Do note this is not the same as desoldering from a single layer PCB board.)
Sincerely,
blu
