There are a zillion 60mm heatsink/fan units. The best almost invariably work well because a Delta 38 60mm fan is part of the package. Offhand, I think it's a good idea to avoid big HS's that use 80mm fans. They are the best, but this is a PIIIE, not a K7.
www.dansdata.com has reviews of many
HSF's.
www.overclockers.com has a nice and accurate list of
HSF reviews. I personally like Vantec's CCK-6035D. Reasonable price, good performance. But, there are a hundred others that work as well.