My name is Santiago Montejo, and I have been into R/C's since 2000, but only into Xmods since 2005.  Xmods are produced and distributed by Radio Shack, they are 1:28th scale electric radio controlled cars.  Fully customizable, XMODS upgrade accessories include body kits, motors, tires & wheels, light kits, and all-wheel drive.  At around $30-$50 US for each starter kit (car, controller, and a few extra parts/tools), Xmods are more affordable than most hobby-grade R/C's...but have almost as many features.  Here is a brief run down on past and present kits/models.

Generation 1 Xmods: Now retired, there were 10 models in the Classic line -- also known as Generation 1 or Xmods Custom R/C's.
1965 Ford Mustang - Blue
1967 Chevrolet Camaro - Red
1997 Toyota Supra - Red
2000 Honda Civic Coupe - Black/Blue
2003 Acura RSX - Silver
2004 Acura NSX - Yellow
2003/04 Chevrolet Corvette C5 - Silver
2004 Nissan 350Z - Burnt Orange
Nissan Skyline GT-R V.spec - Black/Yellow
Subaru Impreza WRX STi - Blue

Evolution Xmods: Introduced in the Fall of 2005, the Xmods Evolution line has a new second generation chassis that can be used with bodies from the Generation 1 Xmods. There are 8 models in the Evolution line - three trucks and five cars.
1967 Pontiac Firebird
Mitsubishi Lancer Evo VIII
2004 Hummer H2
2004 Infiniti G35 Sport Coupe
2006 Ford Mustang GT
2006 Ford F-150
2005 Toyota Scion TC
2005 Nissan Titan

They're many forums dedicated to these Xmods and other small scale R/C's alike - the Xmods however seem to be the cheapest and most popular one around.  Here are a few forums that I have found...

http://www.xmodworld.com/
http://www.xmodsource.com/
http://p221.ezboard.com/bxmodrc
http://www.xmodsforum.co.uk/index.php
http://www.forum.stl-racing.com/

Xmods have been customized by different people in so many ways, one of which is where I come into play...I build custom bodies to fit the Xmod's chassis.  The scale bodies you'll see in here are custom 1/24 static plastic models which I convert into Xmods bodies.  It's not too complicated, but a fair amount of model building experience would make it easy also.

I don't use too much stuff when I'm making these but here's a list of things that will be useful:

1) Dremel - Used for cutting, sanding, shaping, and numerous other things
2) Screw drivers
3) Xacto blades
4) Small ruler
5) Model glue or cement
6) Model putty (Tamiya quick type epoxy putty is very useful)
7) Sand paper (different grit counts)
8) Soldering iron and solder

The process of converting these static models begins by purchasing your model, it has to be 1/24 or 1/25 which are the closest scale you'll find to fit the 1/28 scale chassis.  The Xmods chassis comes in 2 different lengths, the F-150 or Titan starter kits have the longest, and the hummer H2 has the shortest.  Most of these models fit into the wheel base of the Xmods chassis perfectly, but if it doesn't you'll probably need to do a few modifications on the body to make it fit right.  You then have to fabricate custom mounts so that it can snap onto the body - the chassis comes with clip in front so all you need is to recreate a mount socket to slip the clip into.  As for the rear clip - you can simply attach it to the bottom of the model after you have finished it.  I have done quite a few of these, but each has it own differences in may ways.  I try to put in as many details as I can, and over the years I've been steadily improving upon them. 

Here's a few from my collection, click thumbnail to view larger image: