Most programs that list advanced positions are referring to supplemental positions that require you to find your own internship. For the upcoming year, that means PGY-2/CA-1 starting July, 2006.
However, when I was transferring into anesthesiology, most programs I interviewed at stated that an ERAS application could and would be used by the programs for consideration for open spots in the immediately upcoming academic year. In other words, these programs can use the informatio you provide them through ERAS for consideration of any CA-1 positions they may still have available starting July, 2005.
You have to contact the individual programs to determine if this is the case. Some programs prefer that you send a separate application if you are applying for a CA-1 position in the class that has already gone through the match.
I think that it is a benefit to a transfer resident to have a program consider their application through ERAS since it would give you a chance for a CA-1 position in both 2005 and 2006.
For MBMB: If you are finished with your internship and are now in your PGY-2 year, if you don't get a spot for next year, you may as well finish this residency (assuming it is not a 3+ year residency), get boarded in that field, and then go to anesthesiology. That is if you cannot get a position for the upcoming year. At Southwestern, we have/have had board certified internists, pediatricians, critical care specialists, urologists, general surgeons, an FMG CT surgeon, and family practitioners. It was a long road for them, but almost all of them presented superior skills and clinical judgement that allowed them to excel, get great clinical reviews, and thus get great jobs.