Just to tag in a few more comments...
There are different ways of calculating park factors, but it usually involves looking at runs (or HR, doubles etc) scored by both home and visiting teams in home and away games. This effectively normalizes the numbers so that you are comparing ALL players' performance in ALL stadiums.
Since there are still some differences in which players have played in which stadiums because of unbalanced schedules, there are some additional adjustments that can be made to ensure those don't bias the results.
On the righty/lefty comparisons, it's also good to keep in mind that this reduces the sample size...so if we generally feel three year averages for regular park factors provide good info, 5 or 6 years might be needed for a good righty/lefty breakdown.
In general, I think you can trust three-year park factors, as Bobby Roberto showed they tend to confirm conventional wisdom. Most park factors are not big enough to make that much difference in your fantasy choices, but I do tend to limit my pitcher's appearances in the top 5 and my batter's appearances in the bottom 5.
CB Park has already drawn attention because of its high offense as a park factor, though a recent article showed a big day/night difference.
I'm not surprised at all at Camden Yards. While its small size and impact on offense back in the early 1990s gave it a rep for boosting offense, the newer, smaller stadiums, and its huge negative impact on doubles and triples has resulted in it being a pitcher's park in 8 of the 9 last seasons. Last year it played slightly to a hitter's advantage, perhaps because they added some seating, but this year it's been a pitcher's park again, suggesting last year may have just been a litle fluky.