Fred Phelps was a supposedly-conservative Christian pastor, whose vitriolic anti-homosexual rhetoric and actions, including the mantra "God hates fags", and the claim that "God loves everybody… the greatest lie ever told!" (in direct opposition to the basic tenets of Christianity) have gained him a huge negative response.
Once upon a time, Fred Phelps was a good civil rights fighter. He helped remove Jim Crow laws in his hometown and elsewhere. However, later his whole life was devoted to homophobia, to the point of forcing many of his children out of his family for being "pro-gay." Phelps is now dead but the church he founded lives on.
Westboro Baptist Church
Phelps' organization, Westboro Baptist Church, makes a habit of picketing funerals, particularly those of soldiers (regardless of their sexual orientation), claiming that "God hates fag-enablers". Interestingly, WBC also pickets many Christian organizations, including Jerry Falwell's funeral, because those organizations fail to believe that homosexuals should be executed, the viewpoint which WBC holds. In addition to their primary website, "God Hates Fags", they also run a whole site family, with URLs generally on the pattern of "godhatesexample.com". Another notable target is Matthew Shepherd, a homosexual who was murdered in a likely homophobic assault — the protest at his funeral initially gained Fred Phelps a good deal of attention. Phelps also hates Sweden for their policies on hate speech about homosexuals. He has even blamed the 2005 Indonesian tsunami on Indonesia's large Swedish tourist population.
Phelps and the religious right
While many conservatives try to disassociate Phelps from themselves and the conservative movement in general, his politics are very similar to other members of the religious right. Like Pat Robertson and Jerry Falwell, Phelps associates recent tragedies inflicted upon the United States with God's wrath for the nation's growing acceptance of homosexuality. The difference between them lies in Phelps' acceptance, and even encouragement, of these actions as part of God's will, while Robertson apparently thinks God is going too far by letting so many Christians die.
References and notes
Adapted from RationalWiki.