Unsurprisingly, President Bush has endorsed McCain for the next election.  (http://news.bbc.co.uk/2/hi/americas/7279796.stm)  The amazing thing about the linked article is that the headline is only relevant to the first paragraph!  The rest of the article goes on and on about the race between Obama and Clinton.  It's humourous how the press plays this as a neck and neck race, since "winning" each primary isn't enough.  Hillary would have to demolish Obama by over 70% for each of the remaining primaries in order to catch up.  (http://www.time.com/time/politics/article/0,8599,1719614,00.html).  Getting a couple extra delegates with each victory will not cut it.
An interesting side-effect of how these primaries work, now that McCain is locked in, is that many republicans are voting for Hillary.  They don't need to vote for McCain, so their vote goes to the candidate they feel will be easier to beat.