foundationcenter.org
The Foundation Center is a great resources for non-profits seeking funding.  They offer books, classes, and a database listing of grants given in the US which is searchable in a number of ways.  Database access requires paying a fee, but there is a lot of free information for grant seekers on the website.

compasspoint.org
Compass Point is a non-profit that helps non-profits succeed.  They offer classes, and lots of information on managing non-profits, board development, etc.

ontap.org
A listing of professional consultants with specialties in fundraising, information systems, and many other categories, who provide services to non-profit corporations. 

techsoup.org
A site to help non-profits acquire software. Provides forums for discussing software usage, and also lists freely available software.  Different software has different eligibility requirements, but there are lots of things here.  Most of the software is general purpose and not specific to graphics or imaging.