Easy to download right here.
I believe the original idea behind a DXCluster was that it was run on a local VHF packet network. You could then share DX spots with those in your area as propagation would be similar and the chances of others nearby working the DX higher.
There is access to a packet cluster in Kansas City but it is via telnet, which the flcluster can easily use.
Set up was easy and I was off and running.