If you are able to get to Clearspace on the machine you installed it on, it is up and running. It sounds like the install was done on a local desktop machine. In order to make the application available to other computers, the machine where it is installed needs to be configured to be able to handle requests from other machines. Ideally, the application should be installed on a machine that is a dedicated server.
You might want to step back a bit and just make sure that other computers on your network can actually talk to the computer you installed Clearspace on. Try this, open a command line prompt (I'm assuming you're running Windows here):
Start --> Run --> type 'cmd'
and then when you get a command line prompt up, try:
If you get a response from that computer, then great. Otherwise, you've got some name resolution or connectivity issues outside of Clearspace.
Sorry if this sounds obvious, but I have been burned by the smallest details before. If you are using Windows XP (or Vista), double check to make sure Windows Firewall (or any other firewall related software) is not blocking port 8080. I think the firewall is on by default with SP2.
You could also use a port scanner to see which ports on your system are open, and if 8080 is one of them.
On your suggestion I set out to figure out about the firewall settings. Obviously, it is on, then I opened the Exceptions tab and added Clearspace from the program list. That didn't help. Then I was looking for a way to scan the ports but I didn't find any utility.
No solution yet,
I tried to ping the other desktop, and it responded ok. Then I came across another tcp command -net view- that also returned plausible list (ShareDocs) of resources.
So, that part looks ok. What else can be wrong?