gsplsnger,
Darkhut covered most of what you need - you really will not need the CSU/DSU units - a back-to-back (DB60 to DB60 crossover cable)DTE to DCE cable with the pinout for the DB serial interface on the 2500 (which should be DB60)is all you need to connect serial port to serial port.
If you want to use the CSU/DSU then you will need to get a DTE to whatever interface the CSU has on it. The CSUs I have all have a V35 connectors so you will be looking for a DB60 to V35 cable. Then you will need a RJ45 to RJ45 cable to connect the two CSUs together back-to-back (you will have to check Google for the pinouts on that cable).
As for the Ethernet ports you will need a 10Base-T (RJ45) to AUI Ethernet Transceiver and then a straight through Ethernet cable to connect to the switch.
You will also need a console cable and a DB9 to RJ45 adapter to connect to your serial interface on your computer, if you do not have a serial interface on your computer you will need to look for a USB adapter.
If you do not want to mess with eBay you can find any cables, FLASH, DRAM and other parts you need at
I got this site at a Cisco convention - it is where all the CCIEs got most of the cables and parts they needed for their labs! I have bought from him several times with no issues!
Hope this helps!
E.A. Broda
CCNA, CCDA, CCAI, Network +