As ful babu pointed out, it depends on what you intends to do. If you want a generic display system to generate graphics then check out the article on Atmel web site:
www.atmel.com and search for mega163. There is an article "AVR video generator with an AVR Mega163". It is a reprint of an article in circuit cellar issue 150 January 2003.
This shuold give you an idea of how to implement yours in pic.
Hi,
You can use the SAA5244A from philips that is a decoder teletext. Use the bus i2c to control the chip, and the out is scart. And can find more info in one project on the net.