IMHO the best way to have your robot measure distance to objects. Fast and accurate.
If you are using Picaxe, you may find this info useful: http://letsmakerobots.com/node/66
DAGU made a holder for us. It can be used as Pan / Tilt or just as Pan or Tilt:
Oh, and note that if you use it just as Pan, you can mount the sensor on the inside, so it is working from above the center of the servo horn.
My srf-005 only has one set of holes to. It is working, but I am eperiencing this blinking problem
It is probably not related to this but please let me know if you are having similar problems with your.
First I did this: http://letsmakerobots.com/node/155 (Last two pictures). It wasn't good, because it was only mounted in one of the holes.
Then soldered the pinheader on a perfboard, instead of using a connector, glued the perfboad to the servo horn. I didn't have any problems removing it, since hot-melt glue can be "broken" with a reasonably amount fo force.