If you go to this website and give the Obama campaign your email address and/or cell phone number they will send you an email/text message as soon as there's an official vice presidential candidate. They do not actually say that this is how they are announcing it, so this is very likely redundant if you also check the news sites regularly (you can probably expect whatever contact mode you give them to return more fund raising appeals to you than genuine inside information, but I am a sucker so I did it anyway).
Incidentally, does anyone have a preference or prediction for either vice presidential pick?
For a while I thought Joe Biden stood a good chance, but he has not been out in front for the campaign the way you might expect him to be if they were testing him out. Tim Kaine, on the other hand, has been on Charlie Rose, Meet the Press and Face the Nation over the last couple weeks. Each time he has not only been an unshakable Obama advocate but he's also been repeating him own personal and professional narrative. For a while, there was a rumor out there that the web address ObamaBayh08.com re-routed to the Obama Campaign's site. That was true for a while, but now the Obama-Bayh address routes to something unrelated.
Karl Rove was on Face the Nation this morning, discussing the race. He said to expect Obama to pick someone for their political value (Kaine, Bayh) rather than for their skills or policy expertise. The implication, that McCain would not do something so base as to let politics inform his running mate selection, was not-at-all subtle. Still, though, the speculative McCain candidates do not tend to be people who could deliver battleground state electoral votes (unless you think Tim Pawlenty and Minnesota count in those categories, and it's hard to imagine what else Pawlenty would bring to the ticket except an advantage in Minnesota).
For a few weeks Carly Fiorina seemed like she might be a leading candidate. That speculation has died down since her comments about insurance plans covering prescription contraception caused some embarrassment for McCain. Obviously, someone who has the sorts of sympathies for affordable and reliable contraception that Fiorina seems to have is not going to help McCain win over the social conservatives (not that he makes any decisions based on politics, of course). That's too bad for him, though, because when she's been on the TV shows speaking for McCain she's been graceful, witty and tough. She ran rhetorical circles around Senator Claire McCaskill on Meet the Press a few weeks ago.