VGA Resources

Google Search "VGA registers programming",
OSD: Graphics From Chris Giese, containing many code snippets.
Tutorial on VGA graphics including basis of font and line rendering, palette setting, unchained mode, etc.

Graphics Registers -- control the way the CPU accesses video RAM.
Sequencer Registers -- control how video data is sent to the DAC.
Attribute Controller Registers -- selects the 16 color and 64 color palettes used for EGA/CGA compatibility.
CRT Controller Registers -- control how the video is output to the display.
Color Registers -- selects the 256 color palette from the maximum possible colors.
External Registers -- miscellaneous registers used to control video operation.

SVGA resources

90x60 text mode from Chris Giese <geezer@execpc.com>
Changing text mode font -- this also has code for switching video modes without bios