Are you looking for an additional comic book research tool outside of the Overstreet Comic Book Price Guide?
One tool I use and recommend is the Standard Catalog of Comic Books DVD.
The DVD contains information for over 180,000 comic books from the Golden Age to present. It includes series overviews, original cover price, artists, writers, major storylines, character appearances, a rough tally of CGC graded copies and some auction results.
I have the print edition but the large size makes it a little difficult to use. The DVD is a welcome addition and allows me to conduct research on the go.