Latex paint is water-based, so if the paint on the fabric is still dry, you can rinse it out with water. If it has dried, you can try to gently scrape it off with the side of a butter knife, but it may not all come off. Good luck.
It's not a real big deal. I wore this particular pair of pants to paint awhile back because I really didn't care if they got paint on them. Well, I've gotten a bit chunky since then and relized that those pants will still fit me. Now I would really like to wear them and they're splattered with paint.
Just FYI -- Mineral spirits should really only be used for oil-based clean-ups. Latex paint, as has already been said, is water-based, so water (& some soap, if it's gummy) usually does the trick. Once it's dried, tho, I think you're pretty much stuck.