The bolt can be disassembled easy enough using the universal tool that comes with the M14 cleaning kit (It's the handle for the cleaning rod). on the closed end, you'll find what looks like a very shallow scredriver blade; mate the tool on the face of the bolt with the blade just below the extractor. Turn the blade into the extractor and the extractor will pop right off. Of course, the ejector, ejector spring and the extractor spring is likely to pop out as well, so be prepared.
The trick to putting it back together is to compress the ejector/spring combo far enough into the bolt face and with the correct alignment to allow the extractor to be reseated. I have a tool from Brownells that does the job perfectly. Others use a 30 06 cartridge in the chamber to compress the ejector into place with the bolt assembled in the rifle. I prefer the tool from Brownells.
http://www.brownells.com/.aspx/pid=917/avs%7CMake~~Model_1=Springfield__M1A/Product/M1-M14-BOLT-DISASSEMBLY-TOOL
I've never been able to use the tool to disassemble a bolt (it may be due to the use of SAI extractors; the retaining notch is cut deeper than USGI extractors), but it works wonders for assembly.