Yesterday, Android 2.3 has been announced and it includes support for NFC Tag reading. The integration is quite easy because the NFC controller just starts the intent NfcAdapter.ACTION_TAG_DISCOVERED as soon as a tag is discovered.
In order to handle a discovered tag, add an intent filter for this action "android.nfc.action.TAG_DISCOVERED" and read the two extras from the intent like the following in your activity:
byte tagId = intent.getByteArrayExtra(NfcAdapter.EXTRA_ID);
NdefMessage msgs = (NdefMessage) intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);