http://www.irs.gov/businesses/small/article/0,,id=109807,00.html
...
11. A private foundation whose contributions are pooled into a common fund, if the foundation would be described in ( above but for the right of substantial contributors to name the public charities that receive contributions from the fund. The foundation must distribute the common fund's income within 2½ months following the tax year in which it was realized and must distribute the corpus not later than 1 year after the donor's death (or after the death of the donor's surviving spouse if the spouse can name the recipients of the corpus).
Further limits also apply if the donations were made to some specific types of charities.
The only way to not pay at least some tax on a project like this is to create a non-profit, then apply for tax exempt status. As far as I can tell, the OP's organization would meet the requirements for tax-exempt status laid out here: http://www.irs.gov/charities/charitable/article/0,,id=136459,00.html