As Wrasser posted, don't let it touch the air, otherwise acclimate as normal, nothing special. Most sponges don't fair well in tanks unless you supplement phytoplankton as the average tank doesn't produce enough food for these guys. Place it in an area of good but not blasting current, and watch it carefully for die off. If it does start to go, you can try and frag it (mixed results with that really dependant on the species) but get it the heck out of the tank as they will foul your system within hours. Don't let algae get a foothold on it because that almost spells doom.
I've used DT's phtyoplankton with great sucess, and have also grown my own with good results.