I'm a womens 9/10 and my sister a womens 11/12
My feet fit most of the sock patterns (my heel/ankle area is a little long to pull through some of the tighter cuffs, but my sister with a larger shoe size, doesn't seem to have this problem).
It's not too hard to make a few changes, and they don't usually affect the pattern, if you're making it with a heel flap you can lengthen that if you wish and then pick up more stitches in the gusset (choosing to decrease down to the original number of stitches in the gusset or leaving some extra to keep the sock wider).
It's super easy to just keep knitting until they're the right length - infact most patterns have you knit "until x inch(es) from end" and then have you start the toe decreases.
I'm working on the hedera pattern at knitty.com (http://knitty.com/ISSUEspring06/PATThedera.html
) I love it because the heel flap/gusset area is a lot longer than a lot of sock patterns - you might like to try that one for yourself, it's a really easy pattern too!