[sandman]

I was digging for some info on NFC for windows phone 8 and came across some interesting things.

Lots of good info here:
Frequently Asked Questions | NfcInteractor.com

And while WP8 can read plenty of nfc tags, and can write as well, it does not have support for locking the tags :( You'll have to find another option to lock tags.
Frequently Asked Questions | NfcInteractor.com

If you're interested in buying some to play with, it appears these are the ones supported:
Which NFC Tag Types are supported? | NfcInteractor.com