Looks like he's just losing the affiliation...
http://news.yahoo.com/s/nm/20070620/pl_nm/bloomberg_dc
"NEW YORK (Reuters) - New York City Mayor Michael Bloomberg said on Wednesday he was not a candidate for the 2008 U.S. presidential election despite having changed his political affiliation to independent from Republican.
A day after announcing the shift, Bloomberg said -- as he has before -- that he intended to serve as mayor until the end of his term in 2009."