You guys are in for a real treat. WildC.A.T.s series one (the one you probably remember, with the Jim Lee artwork and the cartoon and the action figures) ran for 50 issues. Then Wildcats series two started again from #1 when Jim Lee brought his Wildstorm Comics imprint from Image to DC, and ran for 28 issues. They started again with Wildcats 3.0 #1, and that is already on #17 or so.
The first series had high and low points, the highest of which were #21-34, written by Alan Moore, who is known as THE best writer in comics. Those issues are collected in two trade paperbacks, Homecoming and Gang War. Before that you had more typical “early '90s” stuff with generic X-Men ripoffs and flashy art; light on the actual storytelling. And after Moore’s run, most people say there wasn’t anything great going on either. But there is a TPB called the WildC.A.T.s Compendium that reprints the very first story from #1-4, introducing all the characters and featuring all the flashy Jim Lee art. You can usually find that very cheap on eBay.
The second series got off to a slow start under writer Scott Lobdell, but then Joe Casey took over and pushed it in bold, new, shocking directions. Casey is the writer of 3.0, and his run is getting lots of critical acclaim. Just so you know, most of the characters you may remember will have drastically changed, if they’re still there at all. All of series two has been collected in TPBs (Street Smart, Serial Boxes, Battery Park, and one other), and there is also a TPB of the first storyline in 3.0, called Brand Building.
Comic book writer Mark Millar has a website and message boards, MillarWorld, where fans often discuss the various Wildcats series. Here are some threads with a lot more information than I could offer, but spoilers may abound. These should answer any more questions you have about the various Wildcats series, and what’s up with the characters.
http://www.millarworld.biz/index.php?showtopic=18306&hl=
http://www.millarworld.biz/index.php?showtopic=17092&hl=
http://www.millarworld.biz/index.php?showtopic=16079&hl=