I hope Palin gets in soon, before her supporters here completely flip out.
I doubt she'll be making any such announcement while she's still "on the clock" for jury duty. (That's apparently a 30-day window.) That pretty much rules out July.
But I've been guessing August 15 for a while, even without that particular complication -- that is, I'm thinking the timing may well be related to the Iowa Straw Poll, which is August 13. It's possible she might jump in just before, to try to capture a straw poll win and the corresponding headlines, but that event is all about paying to get supporters in the door to vote for you, which is not something you'd want to try to put together in a week or less. So, an announcement the following Monday could conceivably take the wind out of the winner's sails.
Furthermore, outside of political junkies, very few people are paying attention over the summer, and waiting to get into the race officially until, say Labor Day plus or minus a few weeks, doesn't really hurt with exposure to the general public. It appears that her campaign organization would likely be somewhat unconventional, so not lining up the "typical" organization support isn't as big of a deal, either.
(And, if such a strategy turns out to be a mistake, then perhaps she wasn't the right person for the job after all.)
Mid-August still gives her a good 6 weeks or so for fundraising before the Q3 reports have to be filed with the FEC, so plenty of time to raise money before the first filing.
Funny, I haven’t seen any Palin supporters flipping out. Palin supporters aren’t the ones continually asking, “When is she going to declare?”