TheSixthAxis writes, "Thanks to Divine in our forums for pointing out that there's a free comic available for the PSP's new Digital Comic Reader. If you fancy reading "Transformers: All Hail Megatron #1?, grab the free software, then enter the following code into the Redeem Code box on the PSP's PlayStation Store: A8D2-KMBF-JKE4.
It works, I've just tried it – the download is 45MB."
List of country specific codes:
South Africa - T3C2-TQBB-R6JA
USA - 63N8-R2BF-9E4D
Australia - BGPA-8CBH-DRKL
New Zealand - 7CP5-QTBA-TLRK
Ireland - GMN8-H8B8-QN83
UK - ANTL-MGBH-BN2H