As I understand it - and I'm hardly a tax authority - the tax credit is something that you will complete as part of your 2006 tax return (Next year about this time!). It's not something you're likely to see before then without changing your W4 withholdings.

The HCH I designation is the first generation of hybrids (2003-2005) and the HCH II is the second generation starting in 2006.

Welcome to the forums.

Eric