The first thing you have to do is make sure the server browser is set to view Infiltration All, not LAN games or your Favorites. The box top left in the browser is where you control that. Default is "News". Then, if you look just below the server browser, you'll see a small message saying it's trying to connect to the master server, which will give you the list of available servers. If
that's where it starts giving you problems, well, then we might have a problem.
If it just sits there, trying to connect to the master server, it's probably something blocking your connection to the said server like a firewall or something similar. There have been a few occations during my history with UT and Infiltration that the master server has been down, but it doesn't happen very often. Basically, you'll need to connect to the master server to get the list of available servers.
Then, once you have the list of available servers, it's just a matter of doubleclicking on the server you want to play on.
There are few servers and few players around these days, but it's still possible to have great fun with the (usually) great guys and girls on the servers. One "problem" you might encounter is the new mutators, map packs and weapon packs that the community has made and put on their servers. Allthough all the new stuff enhances the fun and adds a lot to the gameplay, it's a bitch to download everything off the servers if you are on a slow internet connection. It's better to download the packs and mutators off the websites and install them, as they are zipped and made smaller. What you download off the game servers are unpacked files in full size. You won't be able to connect to a server before you have all the files thats on the server you are trying to connect to. I think the INFGermany-server is the server where you'll encounter the least amount of extra stuff to download.
However, playing against and with people is a helluva lot more fun than killing bots. I promise you, it's worth every byte you'll have to download
Looking forward to being shot by you