Ah, life in the universe, my cup o` tea... If life had evolved on Mars (which it very well might have) it would still be carbon-based, water-dependent life just as life is on our planet. Mars is very similar to earth, the major differences being its distance from the sun, and its smaller mass (which just means that it geologically dies before earth does). Thus, life would be very similar biologically and chemically on Mars, but probably not physiologically and aesthetically. The basic idea of life, though, would be the same.