combining PageRank of www & non-www website URLs into one via 301 redirect?

Will a 301 (permanently moved) redirect also forward the associated PageRank of the former site to the latter?

I.e. I use the 301 redirect like this:

http://sawtoothdistortion.com/
becomes...
http://www.sawtoothdistortion.com/
(Click and see.)

The BIG QUESTION is does this also combine the PageRank of both sites into one? (For those of you that are not aware, search engines view the two domains as two separate sites. Check my Google PageRanks to see that this is the case.)

So, will Google recognize and respect the 301 (permanently moved) redirect and "forward" the associated PageRank to the new location?

It appears that this is the case for many popular websites. The Google back links to IBM, Microsoft, Amazon, and Yahoo are the same (same amounts) to both their www and their non-www versions. Also note that those same sites all forward their non-www hits to their www version of their website.

Did they combine the PageRanks of both versions by using 301 redirects?

(This is a crosspost. The dilemma is this: The way Google is supposed to work fits in this forum, but the way 301 (or other) redirects are supposed to work fits in the Apache forum. I wasn't sure where to post. I received no help in the Apache forum so I posted here. Perhaps a mod can clear this up for me, if it is a problem.)