I just talked to a guy here at work that lived in Metarie for 20 years. He said it's really easy to find Causeway Pets. I posted directions in the Causeway Pets Thread
You basically take exit 228 off of the 610, head south for a mile on Causeway Blvd and it's on the right. He said you might need to take 48th st down to Frontage Rd since he wasn't sure if you would be able to get to the pet store right from the Causeway.
Anthony, does that sound about right?