Im 99% sure its fine but I would like to see what other people think.

http://cgi.ebay.co.uk/IBM-SFF-Small-...d=p3911.c0.m14

Would it be good enough to run Ubuntu or Kubuntu well.
Say run a flash website, nothing fancy.

Yes, that should be adequate. May be worth you increasing the memory, but it's certainly not a deal breaker. Good price too.

Just what I thought!
Good to check though
+ yes the memory isnt great but its not expensive to upgrade in comparison

That is the beauty of Linux, any old PC can be still useful and productive with a descent performance.
I got from a friend almost the same specs Dell PC and i managed to do all my Linux experiments and an Apache server. And worked fine.
You can also run a light weight linux distros if you need higher performance.

Yes that PC would work fine with the latest distros. I wouldn't even increase memory unless you want to edit videos or something.

I have run many different Linux distros on much weaker hardware than that. That computer would classify as one my best ones, or THE best one, here.

That should be more than adequate (other than memory, like others have said). I'm running Ubuntu 9.04 on a P4 2.66GHz w/ 1.5GB of RAM, and it's running pretty much smooth as butter. I even have Compiz/3D acceleration working excellently, too. Though that tends to depend more on the GPU than the CPU.

When you say "run a Flash website", do you mean running a server with a Flash website on it, or running a Flash applet within a web browser?

If it's the latter, you should be fine. If it's the former, you might want to consider getting something w/ a little more processing power (just IMO).

I'd say it would work fine. I'd go with low resource DE/WM though, wouldn't do KDE, XFCE would run really well or even just openbox etc. Into tileing window managers perhaps AWM (Awesome Window Manager).

Actually gnome would work fine with that. Buy a stick of 512mb ram for it, you'll be glad you did, otherwise that's all you need and you don't REALLY need THAT. Good luck.

That seller's also got a bunch of similar 1.8ghz machines which would STILL be OK in my opinion. Even cheaper! Something like IceWM or LXDE would fly! Although Gnome should work fine. My PCLOS machine isn't even that highly spec'd.

I wonder if he'd knock a bit more off if you asked for one with no Windows licence...

This will be fine: it's better than the recommended minimum for Fedora, for example, and that's with Gnome. And you can't beat IBM for quality.