Like was told before the sync signals are produced inside an the VGA chip, if you want to connect an VGA to your microcontroller. You can either use an ISA board and control that one. Or build an sync generator with an CPLD, and some verilog code. For more information see this site:

http://www.fpga4fun.com/PongGame.html

I built an VGA sync generator based on an Xilinx XC9536XL CPLD, with an DS89C420. Worked okay, now i am waiting for an denser device to arrive so i can expand it with some video RAM.