How and where can I put in my hours donated at Habitat for Humanity?

[JenniferE1]

Unfortunately, no.
See IRS Publication 526, Charitable Contributions,
 page 7:
“you can not deduct the value or your time or your services”
http://www.irs.gov/pub/irs-pdf/p526.pdf

See IRS Publication 334, Tax Guide for Small Businesses
http://www.irs.gov/pub/irs-pdf/p334.pdf
Chapter 8, under Expenses that you can not deduct
Charitable Contributions