They are typically 5v regulated with ground and output, some may have an
input for a software adjust. Usually the pins are spaced for 14 pin DIP.

1 Electronic Control Voltage (if used)
7 Ground (case)
8 RF output (either sine or TTL)
14 Vcc (usually 5v)

There are usually extra ground pins. Replacements can be found, but are
being obsoleted by various manufacurers. Rather than tearing it open, the
surrounding circuitry will tell you what is what.

Typical:
http://www.vectron.com/products/tcxo/c2400.htm