Brilliant Tutorials with its head quarters situated in chennai, tamil nadu, india is probably one of the best correspondence courses for iit-jee....take it from the mouth of a person who cleared jee-2001 with an air of 934 in general category.
Though there are others like fiitjee etc which advertise a lot and make a lot of fuss, brilliant seems to be working silently and efficiently in order to get more people into the iits.
After classroom sessions, i think correspondence can do wonders, provided of course, that the students themselves are hard working for there is no substitute for hard work and no magic, money or influence can get any student into one of the iits...
For students seriously preparing for the same I think brilliants 2 year elite course as well as 2 year preparatory program are good enough.....besta luck to all students serious to make it into one of the iits through jee-2002.........venky, iitg