There are a lot of other great Lucy/Desi/ILL/etc. sites out there, with tons of info. Here you'll find a lot of them, along with descriptions. I went all through my favorites list and found all of these. :-)
LucyTalk - LucyTalk is a great site with games, tons of info about Lucille Ball, and a great forum! I'm ILoveLucy14 there, and I can tell you that the people there are the absolute greatest!
Kait and Mel's Lucy Page - A page that was just started, but is looking great already!

Lucy Links - A whole bunch of neat Lucy links!
I Love Lucy happypeppynew - A neat site with a lot of facts and fun stuff to do.
I Love Lucy Pictures - A ton of Lucille Ball pictures!
Lucy Library - Tons of information, on lost scenes, episodes, etc. Also has a ton of rare pictures I haven't seen on any other website.
Nuts for Lucy - A really neat Lucy fan site.
The Lucille Ball University - A fun site where you can get a degree in a lot of Lucy-related courses!
Lucie Arnaz's Website - Lucie Arnaz is, of course, the daughter of Lucy and Desi, and she's an accomplished actress in her own right. This is her page.
Cathy's Closet - the ultimate resource for Lucy stuff.
TVParty - This site is for lots of TV shows, but it has awesome stuff on ILL - lost scenes, mistakes, etc.
Lucy, I'm Home! - Sounds from I Love Lucy - a great site!
CDNow - So their emails are a little annoying, but they have the best prices for the Babalu Music CD.
Kayla's I Love Lucy Page - Interesting stuff. This fan really did her homework! (This is where I got the info on how much money Ricky's lost, BTW.)
AbeBooks - Tired of hunting for A Book - Desi Arnaz's autobiography - all over the net? Find it here cheap! These books are used, but I got my copy for $4 including shipping and handling, and it was in great condition!
D E S I - All this talk about Lucy makes you wonder if anybody even cares about the other stars, huh? Well, they do! This is a really interesting fan site about Desi Arnaz, "The King of Cool", according to this site.

Coming soon: Vivian and William links if I can find any and the rest of the sites from my favorites lists.