I've got an older switch that has a serial connection to it, however, I do not have a serial cable for it.

I do however, have a serial to PS/2 convertor and tons of RJ-45 cable.

I just don't know what the pin out would be for putting the RJ-45 to my femle DB-9 convertor.

Google RS-232 pin out and you'll find lots of details.  Here is the first one I saw:  

http://www.airborn.com.au/rs232.html

I know I've seen others but I don't have them handy right now.  

You have eight wires in the RJ-45 so you'll have to drop one pin.  Losing pin #1 (shield GND) is only mildly risky; if you have a shielded RJ-45 you can run it on the outside.  

I suggest monitoring your signals with a break-out box; you can probably get away without routing one of the handshake lines.  It all depends upon your application.  

OTOH - There are lots of inexpensive RS-232 cables available on the web.  Is this project worth saving a few dollars?  
 

Typically, the RS-232 will only use 2 (RX Data), 3 (TX Data), and 5 (Sig GND). If RTS&CTS are required, pins 7&8 are shorted.
On the RJ-45 side, these will corrolate to pins 3,6,and 4 respectively. If you use a RJ-45 to DB9 adaptor, this will be the Black, Yellow, and Red wirs in the adaptor.