This is the web site of a DVD specialty store right up the road from me--and proud sponsor of this forum!
Subscribe to their online mailing list, and each week you'll get the most comprehensive new release listings anywhere, as well as just announced title info with all the glorious details!
Image still has prerelease information. In fact, I think it is a lot easier to go through than it used to be.
Hit the Advanced Search button on their home page. From there you can enter a range of announce dates and it will generate a list for you of all titles announced between those dates. You can also search on release date ranges, film directors, and so on.
I hit it every weekend and pull a list of all DVDs announced the previous week.
If you go to the Laser's Edge site http://www.lasersedge.com
you can get a listing by date of upcoming titles. Use the Advanced Search utility that can be found in upper left of title bar. The first selection lets you search by specifying a date field.
Also useful, is the search function that let's you search for changes in the database, again by specification of days. This allows you to spot new announcements and other changes.
Laser's Edge updates daily and the site is kept very accurate.