You can often find new release information for comics (in full and for free) online. Most publishers have their own websites which highlight new series and news.
For more detail the various distributors release online catalogues each month with all the newly solicited comics. Catalogues are normally updated around the last week of each month.
Penguin Random House – catalogues at Penguin Random House Comics Retail
Boom
Dark Horse
IDW
Marvel
Lunar Distribution – catalogues at Lunar Distribution
Abrams
Ahoy
Archie
AWA
Bad Idea
Black Mask
Cartoon Books
Clover Press
CSN
DC
Drawn & Quarterly
Ex Posse
Fantagraphics
Floating World Comics
Image
IPI
Mad Cave
Massive Publishing
Oni Press
Papercutz
Pow Pow
Rebellion
Rekcah Comics
Rocketship
Scholastic
Silver Sprocket
Strangers
Titan Comics
TwoMorrows
Udon
Uncivilized
Vault Z2
Zdarsky
Diamond Comics USA / PreviewsWorld – catalogues at previewsworld.com
Dynamite Entertainment
Aftershock Comics
Ablaze Comics
Zenescope Entertainment
(and others)
