Tangotiger has released his projections for 2005 batting and pitching stats, based on a system he calls “Marcel,” because it’s so simple that even a monkey could do it (remember Ross and Marcel?). If I recall correctly, Tango basically blends each player’s previous experience 5/4/3/2 for hitters, and 3/2/1/2 for pitchers, where the first three components are each of the last 3 years (most recent year first), and the 4th number corresponds to league average.
I believe Tango also adds a simple aging factor for each player.
You can download the zipped file of Tango’s projections. You might also be interested in Dan Szymborski’s ZiPS projections, which are also available for download. I have to admit that I don’t know how Dan calculates his projections.