As long as you do well in the fall semester, it's a good idea to send updates to all the schools that you have open applications with at that point. Some undergrads offer to send only semester grades for a reduced rate/free altogether. A lot of schools may not require official documentation, though. They may just take your word for it if you send it in writing (check with each school on this). This is okay from their perspective because if you lie, they'll eventually find out and then they can revoke your acceptance.
To Rugger, I'd definitely let your schools know one way or another about your spring grades, assuming you just completed your 6th semester. Otherwise, adcoms have only 5 semesters of grades to look at.