For those of us who were following the OAVs via fansubs in the late 90's, this was big news. Now that the series has been complete in North America for over 2 years, it's rather stale. But I'm keeping this up anyway, primarily for nostalgia ^^;
The first TV episode aired on July 7 (7pm on the satelite station WOWOW in Japan) 1999, and since then it was a weekly series, ending at 13 episodes (what? Over so soon? ;_;). The series features the same character designer and director as the OAV series. The storyline picks up after the OAVs'.
It has the same feel as before though there are some minor changes and additions. For one thing, there are new characters ^^ There's Nanaka's mother and younger brother, Takeo's little sister, and Ayanojou's mother. (see my gallery for character designs) There's also a group of girls who make up the Aburatsubo Defense Force ^_^;
There are also changes to a few character designs. Akane, for example, wears her hair in pigtails as well as down long (in the OAVs she wore it in a few other styles too, but hey, pigtails are something she hasn't done yet ^_-). The main noticeable one I can see is Mizuha ^^; They've altered her uniform to something a little less seductive (It accentuates her chest less *cough*), and she has shoulder-length hair which makes her look younger. But seeing as how OAVs can get away with more than a TV series can, it isn't surprising that they would do that ^^;
A portion of the Animage July article featuring the TV series has been kindly translated by Tarra Nakatsu and can be found here (if you'd like to read up on more specifics about the changes and whatnot ^^). She's also kindly given me an episode list with translated titles of all thirteen episodes, which can be found here ^_^ They may not match the North American release exactly, but it should give you a rough idea.