[brownsfan]

If Opportunity is Spirit's twin, wouldn't it make sense to tell it to go to sleep until they figure out the problem on Spirit?

Yes, it would, but they've figured it out. Before the weekend is done, both rovers should be working. It had to do with having too many files in the flash memory, and when Opportunity woke up, they began deleting files immediately so it wouldn't happen to Opportunity too. They are deleting files from Spirit, and she should be good as new! :)
I haven't heard about the heater problem on Opportunity, anyone know if that was fixed?

[Fitzcarraldo]

The heater problem on Opp. is still being studied - but they will study it as it goes.

[Fitzcarraldo]

CSPAN

Click on the above link and find "NASA Mars Missions Briefing" under "latest video"- for a replay of today's press conference.