Sure.

Do you have the regular lab map first? You need to already have the Secret Laboratory Map available to use the Petpet lab map.
If you do, then you go here:
http://www.neopets.com/games/treasure.phtml
and click on Petpet with the 9 lab pieces in your inventory. I think there is a button to confirm, but I don't remember. After that, you should be able to use it.