Over at the Patent Prospector we get an authoritative answer: yes, the patent application is now enforceable. Quoting from Iskra:
Provisional patent rights and the 18 month publication of applications arose from the American Inventor’s Protection Act (AIPA - 11.29.00). Before AIPA was enacted, the applicant had no rights until the patent was granted. Contrastingly, amended 35 U.S.C. §154(d)(1) (thanks to AIPA) now provides a right to obtain a reasonable royalty from any person who infringes the invention during the period that begins upon publication and ends when the patent actually issues.The ways in which enforcement of these claims would restrict your right to create are almost innumerable. Want to do something about it? Write your representatives.