At least, this is according to the weekly standard:
FRED THOMPSON IS RUNNING for the Republican presidential nomination. In a conference call Monday, Thompson addressed a group of more than 100 supporters and fundraisers whom the campaign has dubbed First Day Founders. He told them that he would be setting up an organization that will allow him to begin raising money and recruiting staff.
In official campaign finance parlance, the move represents a shift from “giving serious consideration” to a presidential bid, as Thompson said he would do back in March, as a non-candidate, to a “testing the waters” period where one is, in effect, a candidate-in-waiting with a campaign-in-preparation. Thompson advisers point out that the new testing-the-waters entity is not quite a campaign committee, though it will officially begin accepting contributions on June 4. On that day–the First Day, as it were–the campaign will take in donations that it can then tout as an impressive one-day haul. A corollary benefit will be that news reports about Thompson’s non-entry entry will run on June 5, when the declared candidates will meet in New Hampshire for their third debate. (Thompson won’t be required to disclose his donors and the amounts they give to the Federal Election Commission until September.)
Unfortunately I don’t think he’ll make it into the upcoming CNN debates in June but his news coverage will win them hands down (despite Ron Paul). However, this is yet another indication that an announcement is imminent.