I've had this functionality in PIDRNG for some time, but I figured that I should probably move it to its own thread by now, since the checking for both kinds of wondercards is done. The wondercard portion validates the PID and IVs of a given wondercard and the shiny portion validates the PID of shiny wondercards.
http://pokemon.thundaga.com/research/apps/WondercardInspector_10.exe
Usage is simple. For regular wondercards. use the tab labelled as such. For shiny wondercards, use the so-labelled tab. Be aware that finding a match for a plain wondercard may take a few minutes, possibly up to 10, maybe longer. Also, due to the large search space for regular wondercards, you will often find a hit. There is no way to reduce the search space and give better accuracy. However, even if it isn't the exact creation seed, the inspector finding a hit means that it is valid regardless. Shiny wondercards have very specific, easy to determine, PIDs. They're easy to check so those will be instant.
...and no, I didn't rip off the PID-checking functionality on Pokecheck. Might as well get that out of the way now. I showed Pokecheck how to do it in the first place. I've had the functionality in place for some time in my own app.