i bought this of eBay (11/01/2011) for £25 inc P&P
2x Pentium 3/512 L2/500MHz
1Gig of ECC RAM
4x 18.2Gig 10k RPM 160MB/s SCSI Hard Drives
12/24 Gig Tape Drive
Smart Array 221 RAID Card (now upgraded to a Smart Array 3200 RAID Card, 64MB of read/write cache)
Remote Insight Lights-Out board
2x 10/100Mb Dual network cards
more specs - (http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&taskId=120&prodSeriesId=254604&prodTypeId=15351&objectID=c00411953)
i did have 1 or 2 problems with installing a Linux OS (but not with Windows 2000 and XP)
when i tried to install OpenSuse 11.3 it would freeze, after a bit of web searching i found that by adding some switches to the GRUB boot options (nousb nousbstorage apm=off noapic noht nomce skipddc) then the install went fine
the other problem was that OpenSuSE would freeze when the Cap-Lock or Num-Lock key was pressed, also would not reboot, but again after some web searching i found out how to access the Advance Options in the BIOS (System Configuration Utility) by pressing CTRL+A and to change the APIC mode to Full Map that seemed to fix the rebooting problem, when i was in the Advanced Options i found a option named Hot Plug Keyboard, that was Enabled, i Disabled that and that seem to fix the keyboard problem, it still wont fully power down when halted, but that's no big deal.
all in all a good buy i think.