According to many sources Shakugan no Shana has a season 3 coming up! It was only a matter of time, I guess.

With season 2 in retrospect I look at this with mixed feelings, although I’m excited about it, frankly. Hopefully the romance won’t be as… annoying in terms of plot development – Yuji + Shana ftw! Haha.

Will be released October 2009.

The announcement was originally from the July issue of Dengeki Bunko （電撃文庫） magazine.

This will be a third season, but the story may or may not be a continuation of the same storyline from the first two seasons. There is much speculation around this and not many details, but I’ll post more info as it comes. 

Source: AnimeNewsNetwork
More: http://animelife.co.ua/news/197-novyj-sezon-shakugan-no-shana-budet.html