I don't know of any grid plug-ins but there's a tutorial that teaches you how to make grids using patterns. It was written for Paint Shop Pro but it can be easily used for any other graphics software.
http://www.jasc.com/tutorials/nieuwenstein/grids.asp?
Looking for a grid generator plugin
create grid
check www.humansoftware.com ottopaths, this is creating grid as paths within photoshop you can then fill the way you want
Grid Generator
Oops! I should have included the following in my previous message instead of the email address.
www.kinneticfx.com
www.kinneticfx.com
Does anybody know of a photoshop version of Gridliner or GridDraw for photoshop 7?
this site www.kinneticfx.com only has them for photopaint
this site www.kinneticfx.com only has them for photopaint