Any steam cleaner that has the hand-held attachment - that is what you need. And from expeience, I highly recommend the use of hot water - one it gets put through the machine and squirted onto the carpet, it cools off alot so no worries about damage from the heat - by the time it hits the carpet, it will be much cooler than what it was coming straight out fo the faucet.
I owned a '97 Cherokee for about 1 yr - when I bought it, it had a lot of the salt grime in it - using the steam cleaner made the carpet look new for the most part. My tips would include:
1) Plan to do it with the few following days being great, sunny weather - you will want to be able to leave the windows down etc to let it dry out well.
2) I have had the best results using the cleaning/soap/detergent solution once or twice, then using just clear water 2-3 times more. It seems that the detergent solution loosens things up, but using just straight water really lets the vacuum suck the filth out better.
3) Go over it many times with just the vacuum part after you've use the detergent and then the water - you want to try as hard as possible to get as much moisture out as you can with the vacuum. Take your time, overlap your passes, and go over it a lot to get all the liquid out. This may be the most time consuming part - even when you think you've got it all, go over it again - this step makes the drying process go much faster.