Presidential Funding Act of 2007 - Amends Internal Revenue Code provisions relating to public financing of presidential election campaigns to: (1) quadruple (1:1 to 4:1) the matching rate for contributions to primary election candidates; (2) lower from $250 to $200 the limit on individual campaign contributions; (3) increase the presidential primary qualifying threshold from $5,000 to $25,000 in 20 states; (4) require presidential candidates to participate in the primary payment system to be eligible for general election payments; (5) move the starting date for payments to primary candidates from January 1 of a presidential election year to six months before the earliest state primary election; (6) allow additional payments and increased expenditure limits for candidates who face opponents who do not participate in public financing and who raise more than 20% of applicable spending limits; (7) designate the last Friday before the first Monday in September as the date for payments to eligible presidential candidates; and (8) increase from $3 to $10 the presidential campaign tax return check-off amount.
Amends the Federal Election Campaign Act of 1971 to: (1) increase expenditure limits for presidential primary campaigns and eliminate state primary spending limits; (2) limit political party general election campaign expenditures to $25 million, with an additional $25 million allowance after the party's candidate is nominated; (3) prohibit political parties from spending unregulated funds (soft money) on their national conventions; and (4) require presidential campaign committees to disclose information about bundled campaign contributions (series of contributions exceeding specified threshold amounts).