It's a Hibiscus rosa-sinensis 'El Capitolio' the salmon variety, which is a sport of the original red El Capitolio. It's also known as a Poodle hibiscus.

What is a sport? (In case you don't know) The Gardenweb glossary defines it as "An abrupt, naturally occurring genetic change resulting in a branch that differs in appearance from the rest of the plant, or, a plant derived by propagation from such a genetically changed branch."
Basically, a branch with salmon colored flowers showed up on a red blooming El Capitolio plant. Someone took cuttings of that branch and there it is - salmon colored El Capitolio hibiscus plants!
Nice find at a WalMart! I have both the red and the salmon. Love 'em.

Barb

Great! Thanks for the ID ...