sweatdrop You joined a TMM guild... when you hardly know anything about it... you have a lot to learn.
sweatdrop First of all, I'd suggest for getting to know the characters, you check out
this site. Cinna set it up as the old guild website; although it hasn't been updated in a while, it's still there and has good information on the characters.
As for the plot... here's a basic description. There's only basic spoilers that are found out in like the first few chapters and episodes anyway, so... yeah.
Momomiya Ichigo is your average, pink-haired, teen-age girl who has a crush on the school's pretty boy, Aoyama Masaya. Or at least, she
was normal before a genetic experiment (conducted by Shirogane Ryou and Akasaka Keiichiro) combined Ichigo's DNA, along with the DNA of four other girls (Aizawa Minto, Midorikawa Retasu, Fong Purin, and Fujiwara Zakuro), with the DNA of an endangered animal. In Ichigo's case, she has been combined with the Iriomote Mountain Cat (or something along those lines), which of course leads to her adding -nya to the end of many of her sentences, as well as cat ears and tail popping out when she gets stressed. However, this DNA also allows her and the other girls to transform into the superhero team Tokyo Mew Mew, which is meant to protect the world from the threat of the chimera animals, creatures infected with alien parasites. Oh, and Kisshu, Pai, and Taruto? They're the antagonists, although Kisshu appears to have a crush on Ichigo.
If you want to learn more, the entire manga is available in the United States (7 volumes, plus 2 of a sequel series, "A La Mode", which chronicles the addition of a new Mew, Berii.) Also, there is the anime, which is somewhere around 52 episodes (I think). 4Kids, unfortunately, got the rights to dub the first 26 of those episodes into the horridly mangled "Mew Mew Power", although they have only shown the first 23. If you want to see the original anime, however, it should be easy enough to search for subtitled episodes on YouTube. (If you don't know what that is... google it.) Although... you might want to be careful what subs you look for. If it is a "funny fansub", then they won't be accurate and will probably be very inappropriate. (At least, I've noticed that in my search for subtitled episodes of Yugioh GX.)