eQualityGiving has founded the "Yes, I Do" Campaign. The website is a resource tool pulling together US House and Senate members PRO Same Sex Marriage statements. Here, you can read which states and politicians have already gone on record with their support. Also, there is a feature to submit any missing Members of Congress and add their quote in support of same sex marriage.
A quick browse through the page yielded a variety of quotations from human rights superstars like Diane Feinstein and powerful statements from across the country, such as Congressmen John Lewis, of Georgia (D) who said, "It is time to say forthrightly that the government's exclusion of our gay and lesbian brothers and sisters from civil marriage officially degrades them and their families. It denies them the basic human right to marry the person they love. It denies them numerous legal protections for their families... This discrimination is wrong. We cannot keep turning our backs on gay and lesbian Americans."
Another Congressman, Keith Ellison of Minnesota (D) echoed the concerns over "the fact that voters in a number of states came out in support of Constitutional amendments banning gay marriage and civil unions. These were blows to the rights of all people. I am not gay, but when my gay neighbor suffers from discrimination, then I suffer and so does the entire community."
And New Jersey Congressmen Rob Andrews (D), had this to say in reference to gay marriage versus civil unions; "I support marriage equality. The recent commission report on civil unions was pivotal in my thinking. The civil union law has failed to give gay couples equal rights."