Endorsements are one measure of how well a campaign is doing. I think they are probably the least accurate measure, behind: early state polls, national polls, fundraising and the blogosphere. But they nonetheless provide an interesting perspective.
The Washington Post has done sterling work in tracking state legislator endorsements in Iowa, Michigan, Nevada, New Hampshire and South Carolina here.
In summary, this measure shows Joe Biden and John McCain performing rather better than the polls suggest. McCain actually leads the GOP endorsement race in New Hampshire and South Carolina and comes second in Michigan. Mitt Romney dominates Michigan, Nevada and Iowa.
On the Democrat side, Iowa looks like a three way between Clinton (leading), Obama and Biden. Edwards trails and Richardson has no presence at all. Biden also looks credible in South Carolina where he almost equals Clinton and is well ahead of Obama. Edwards leads in this state. Clinton cleans up in New Hampshire, though Chris Dodd shows surprising strength, almost equalling Bill Richardson, though well behind the second tier of Edwards and Obama.