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.