I'm not any expert (but I'm trying!!) -
Basically, the HBP is the government allowing you to 'borrow' from your RRSP's to purchase your first home instead of saving it for retirement like they're intended. This must be for the first home you buy & you must be living there.
I'm assuming you know that with RRSP's, your contributions are deductible when you make them, and you get taxed on what you draw when you retire.
Under the HBP, you can withdraw up to $20,000 from your RRSP's without tax being withheld/payable, and have 15 years to pay it back.
The biggest advantage, imo, is you're getting the deduction from your taxes, and you're using that to your advantage to buy a home (ie, you make the contribution to your RRSP's, get a refund, then you can use that money you contributed towards your home).
You are, however, missing out on any growth of your RRSP's, however, with the way housing prices are skyrocketing, it might not be a bad idea.
This link, and your friendly neighborhood accountant, can give you all the information you need:
http://www.cra-arc.gc.ca/tax/individ...bp/menu-e.html