AS you already might know the Red Ring Of Death (RROD) is a heat problem caused by the (bad) design of the Xbox 360. In these cases the temperature gets too high and the glue between graphic and CPU components melts, cuasing the heat sinks/coolers to get off the components.
If it is in warrany (and please check before you open op your xbox!) then get it to xbox. In 9 of 10 cases your xbox will get a motherboard replacement. Do not ever send in your harddisk. memory card or faceplate when UPS picks it up.
If it is not in warranty, but you're not that good in toying with electronic components, bring it to the closest radio shack or something like that. Get it repaired for a couple of bucks while you wait.