I feel that while there may be some expression of freedom from social classification for Tank Girl through making out with another female, I'd say that the male fantasy theory is more likely. The movie is based upon a comic, and appears to me as a complete joke, leading me to believe that the make-out was most likely meant to pander to male audiences. I mean, when a movie combines explosions, super-kangaroos, and cybertronic antagonists in a post-apocalyptic world, is it really necessary/sensible to search for a deeper meaning?

Seriously, speaking from the point of view of a male fantasizer, I think it's the second option in most cases.

In the comic, wasn't Tank Girl homosexual?

(I read this on Wikipedia because I was curious for more details on this movie) There was something mentioned about this movie's attempts to portrary female empowerment (that whole "We don't need men" thing): "Rachel Talalay, longtime producer of John Waters, had fallen in love with the comic after receiving an issue for Christmas one year from her stepdaughter, and set out to make 'the ultimate Grrrrl Movie.'" As true as that may or may not be, I also acknowledge that these women are eroticized.

I thought that they were eroticized, but, hell, i had no problem with that! I think that the difference between Tank Girl and a movie like Barbarella is that, in Tank Girl, the main character is really acting of her own accord. Besides the fact that she doesn't have the whole "too-innocent pseudo-virgin but not really" nature of Barbarella, Tank Girl is just in every way a badass. There could have been many different ways for her to save Jet, but she CHOSE the make-out route.
Also, the Tank Girl of the comics wasn't homosexual. She definitely had some bi leanings, but I think that the movie did a fantastic job of portraying the comic that I remember/love.
Basically, this movie=amazing :)