I wrote up two diaries which will get you started as to what happened with the announcement and the aftermath of it.
This diary is about the speech Kerry gave on the day he announced he wasn't running. He talked about Iraq but he also gave a dire warning about Iran. Kerry's words resonated with dailykos big time, I can tell you that:
http://www.dailykos.com/story/2007/1/25/152730/745The second diary was about how horrible the MSM has treated Kerry -- just awful. However, I think things will improve (if this past week is any indication), but you should know what was done to him in the last couple of weeks:
http://www.dailykos.com/story/2007/2/5/143453/0122As Karynnj said above this post, johnkerry.com is a really good bet, because you can watch his appearances and check out the blog posts to know what's up. But I'll highlight a few posts, you might really like:
A Thank You from John Kerry to . . . . us
http://blog.johnkerry.com/2007/01/thank_you.htmlThe Story of Brian Freeman and how his loss of life in Iraq affected Sen. Dodd and Sen. Kerry
http://blog.johnkerry.com/2007/01/brian_freeman_an_american_hero.htmlWhat Sen. Carper said about Kerry (really, really nice)
http://blog.johnkerry.com/2007/02/fighting_global_warming_part_i.htmlThen just check the last week's posts for all of his appearances.
Of special note is a beautiful and extraordinary diary Prosense wrote (as AllDemsOnBoard) on dailykos about Kerry's 4 decades of fighting for the truth
http://www.dailykos.com/storyonly/2007/2/1/8430/89348