I’m going to make this short and sweet because I know that you just want to find out where the g-spot is and that’s it (note that I’ve also got an excellent video with diagrams at the bottom, as well as some advice on advanced techniques such as g-spot orgasms during intercourse, squirting, etc.), so here we go:
- The g-spot is located 1 to 3 inches inside the vagina.
- The g-spot is on the anterior (that means the front) wall of the vagina.
- It has small ridges on it like the ones on the top of your mouth so that once it is stimulated (for more information on how to do that, see: How to find the g-spot on the front page), you’ll be able to feel a small ridged bump about the size of a quarter.
- In my experience it’s typically located closer to 3 inches in than one, but that’s just my personal anecdotal evidence.
Also, just a tip, it’s extremely important that you get the girl aroused and wet first because if you don’t then not only will your little “exploration” be painful but it won’t work because if she’s not sufficiently stimulated and aroused then the g-spot won’t show itself. Also, I’ve got an excellent video here to educate you about the g-spot, it’s location (includes diagrams) and how to stimulate it, check it out:
Advance G-Spot Stimulation: Intercourse, Squirting, Etc.
If you really want to advance from just finding the g-spot to learning all the best techniques to stimulate it during sex, including stimulating it with your penis during intercourse (what positions, what speed, etc.) then I highly recommend you check out this resource called The G-Spot Sex Manual (aka “Female Orgasm Black Book”)–this is something my girlfriend and have tried, and we are very pleased with it so far, everything they recommend that we tried left her very happy (as in “covered in sweat with her legs shaking” happy 
), so go get it, try it out, and make your girl happy, too.