Lots of options, but the most common volume is probably 1.25 quarts/pound for the mash. I assume by sparge you're talking about rinsing your grains in another pot to get the residual sugar out, in which case you can either use the same volume or decrease it if your boiling pot will not handle the total volume from the original mash vessel plus the spage (which is what I end up having to do...1.25 qt/lb for the mash and 1 qt/lb for the rinse/sparge). If you're boil pot volume can handle more, you can try a thinner mash of up to 2 qts per pound, which may increase your efficiency acc to a recent thread here on the boards. You can then rinse/sparge with 1-1.25. When you're trying to figure how much wort you'll have to boil, remember that your grains will absorb about 0.2 gallons/lb of grain, give or take.
You might get more informed responses than this, but if not, these options will work for you.
Good luck with it...