Hi megaman,
all the tombs at Burren now have brand new signs like this: http://www.themodernantiquarian.com/post/55882
making them extremely easy to find. Burren SW is the first sign you come to as you walk up the forestry track marked on sheet 26 at H065346. In case you don't have the map: head out of Blacklion on the N16 but get off it on the left fork a little outside the town. Take the 1st left up the hill (signposted Legeelan, I think) and the track has a sign about a mile and a bit up this road.

Happy hunting

Andy