Eh thats not quite true, certainly they had lovers that they fought with, but for most Spartan men the homosexual relationships would end when the younger of the two would become an adult. You're thinking of the Sacred Band, an army composed of homosexual couples from Thales (i believe). They were undefeated until the entire unit was wiped out at some battle that I can't remember. Homosexuality was a common thing in the ancient Greek world
The spartans fought just like any other greeks did, so you can look it up in any text book on Greek history. They just fought better, not necessarily different. They made a point of basically fighting most battles the same way, so there weren't exotic "techniques" per say.
Also, you must know that any historical information about the Spartans is at least second hand, as they had no writers or historians of their own, and the people who did write about them probably exaggerated certain points.
So anyone claiming to sell you secrets of spartan fighting techniques are, most likely, full of crap.
