This should be an easy question for many out there.  I know the criteria: 130 ABs, 50 IP, 45 days service outside of September roster expansion.  I also know for 100% fact that service time is cumulative from year to year, ie. on MLB roster 20 days one year, 30 days the next, and lose ROY eligibility.  I also have always thought that ABs and IP were the same way, however, I have recently been told by someone who interpreted the official MLB rule differently from me that IP or AB must be achieved in a single season.

So for example, if a guy pitches 32 innings in 2006, then 23 in 2007 (he now stands at 55 career IP), but does not surpass 45 days service time outside of roster expansion, is this pitcher ROY eligible in 2008?

Here's MLB.com's official wording:
"A player shall be considered a rookie unless, during a previous season or seasons, he has (a) exceeded 130 at-bats or 50 innings pitched in the Major Leagues; or (b) accumulated more than 45 days on the active roster of a Major League club or clubs during the period of 25-player limit (excluding time in the military service and time on the disabled list)."