Here's my PAR readings using a Quantum Apogee PAR meter with the 3w LED's I have. My LED's look to be the same as the ones on the link Doug posted.
LED
6" below fixture (just above water line) - 1350 ppfd
1" below water - 830 ppfd
12" under water - 310 ppfd
24" under water (sand bed) - 160 ppfd
For a comparison, here's my PAR reading for some different MH's I used on my tank.
175w Iwasaki 15k MH
6" below fixture (just above water line) - 1575 ppfd
1" below water - 625 ppfd
12" under water - 325 ppfd
24" under water (sand bed) - 200 ppfd
175w XM 15k MH
6" below fixture (just above water line) - 500 ppfd
1" below water - 225 ppfd
12" under water - 110 ppfd
24" under water (sand bed) - 80 ppfd
250w XM 20k MH
6" below fixture (just above water line) - 1280 ppfd
1" below water - 375 ppfd
12" under water - 220 ppfd
24" under water (sand bed) - 155 ppfd