Any ideas on what to do with a board that condition is unknown?
Getting the power light to work is step 0.  Once you know it might be in working condition (You might also want to see if you can poke around with an oscilloscope and see if anything appears to be working).  After that, step 1 is finding the datasheets/manuals.  You want the quick start manual and/or one-page advertisement for the basic specs, then the datasheet for the board, the manufacturer's datasheet for the processor, and the ARM datasheet(s) for the processor.  Here's what I found with some brief Googling: 


Quick Start User's Guide
eCos page
ARM 720T Technical Reference Manual


Step 2 is to blink an LED, and Step 3 is to start up some kind of communication between the device and a development PC.  Step 4 is completely up to you.

Alternatively, you can load the device with whatever OS you want to play with (this platform appears to have good OS support in spite of its age), and work from there.  I'd advise more knowledge about the inner workings of the processor before going too far here, but it's your choice.  

Be aware that the board has been discontinued since around 2003.  You might have some luck bugging Cirrus for support, and seeing if you can convince them to send you a newer version :)  

Note that they do say that they can't provide applications engineering support for discontinued products.

Finally, I'd recommend against using this board if your real goal is to learn to develop software for the ARM processors.  This is using a v4 architecture from the early 2000s, they're on v7 now.  From the "Classic Processors" section of arm.com: 


  While the ARM7 processor family
  continues to be used today for simple
  32-bit devices, newer embedded designs
  are increasingly making use of latest
  ARM processors such as the Cortex™-M0
  and Cortex-M3 processors, both of
  which offer significant technical
  enhancements over the ARM7* family.


This is more for the continuingly and overwhelmingly popular ARTM7TDMI than any other processor in this lineup.  I'd strongly suggest, if you want to learn software development for ARM processors as a marketable skill, that you learn on a newer processor like a Cortex-M0 or -M3 (or a Cortex-A9 if the better embedded OS support and MMU on the 720T is important to you).  If you just want to have fun with some donated hardware, then you're going to need some serious Google-fu in your fingertips.

*The ARM7 family and ARMv7 architecture version are very different things. ARM7 is [mostly] related to ARMv4, but also ARMv3 and v5, and ARMv4 is related to ARM7, 8, and 9.  The Cortex family and v7 architecture are mostly equivalent.  See the Wikipedia article for more information.