I have a 2000 Sebring LX with 62k miles on it.

It has a check engine light on, the speedometer and odometer do not work and I have a very noticible loss of horsepower (it takes an extra 1k of RPMs to get maintain speed). It all suddenly happened today. I was just driving through the neighborhood around 30 mph, stopped then noticed that the speedometer was not working and it seemed to take more to go forward. I also noticed that the upper right portion of the speedometer was dimly light.

Any ideas what this might be? I hope it is not as serious as I think it is.

 

Could be a lot of things. The place to start is to check for error codes that are causing the check engine light to go on. If you don't have an OBD (on-board diagnostics) code reader, go over to the nearest Autozone and ask them if they will read your codes. They usually are glad to do it for free. Once armed with that information, you can begin to decide what to look at next.
The failing lights could be a symptom of a weak battery, or perhaps a bad ground somewhere, or a corroded electrical connection, a bad alternator or something else, I'm sure.
But grab those codes first.
Check back in here to keep us appraised of your progress.

 

It sounds like you may have dropped into "Limp mode". Which is 2nd gear only. It's not necessarily a big problem that has caused this but it needs to looked at quickly before any significant damage occurs from running the engine at high rpms for too long.

It may be as simple as a sensor on the tranny no longer reporting speed or a disconnected plug. But the codes are the best first place to start.

 

Codes are always the right place to start. My local Autozone (In CA) has stopped lending or using OBD code readers, supposedly as a result of the auto repair lobby complaining about code resets and all of the "Pollution" this is causing. (Well, I myself am just crying about the ozone, but I live in California so I am used to being around all these tree hugger types.)

But if you have to start looking for a problem, after checking all of your fuses, I would start with all of the wiring harnesses that head anywhere near the tranny.