The bottom bracket should get the same overhaul as your wheel hubs. Replace the bearings. This requires some bottom bracket tools (to remove the lock ring and usually a pin spanner to remove the adjustable cup) as well as a crank remover. These tools are very worthwhile investments, and learning to do it yourself invaluable. The Park Tool website provides you with some excellent info to get you started, with pictures and detail on the tools you need.

The Freewheel probably does not need anything but I always give them a thorough cleaning with a little WD40 and a freewheel "tooth brush" available at your LBS. The serated end is the most effective. Give it a LIGHT lube afterward, since WD40 is a Degreaser NOT a lubricant.