she_borderline:
There is a good Wiki write-up about Maria-sama ga Miteru and Anime News
Network has synopsis for the 2 seasons in their Encylopedia.
(a google search of "Maria-sama ga miteru" will give you links to both)
Other than that, you're just going to have to find the time to sit down and watch the shows
Fansubs are still available of both seasons, along with the current run of OVAs.
As for the Fourth Season. Yata!
The website promotion certainly confirms more development in Yumi and Touko's relationship (Touko is a far more interesting Soeur candidate than Kanako).