Actually, I prefer ALClient as my free client. It's not ZMud, but it has more features than a new player would care to use, and I liked how easy it was to set up. (I just took a look at Putty's web page. Ick.)
Available here:
http://www.ashavar.com/client/
Once you install it, you just need to put our game's location under: Connect/Connect to Remote Host. Our address is mud.shatteredkingdoms.org. The port is 1996. After you connect, go to File/Save, then set autoload last cfg file. That will keep our information in memory, so you don't have to retype it every time you connect.