ACLU =/= this thing you call "the Left".
The ACLU defends civil liberties, even cases in which the use of them is something we find repugnant. That's the deal with free speech. People will use it to say things we don't like. It's part of the package. What's guaranteeing your right to free speech also guarantees theirs.
The ACLU defends Christians as well as other religious groups, although I am not sure how Christian Fred Phelps really is, no matter what he says.
http://www.aclu.org/religion/tencomm/16254res20050302.html
Some highlights:
"August 4, 2005: ACLU helps free a New Mexico street preacher from prison.
November 20, 2004: ACLU of Nevada supports free speech rights of evangelists to preach on the sidewalks of the strip in Las Vegas.
November 9, 2004: ACLU of Nevada defends a Mormon student who was suspended after wearing a T-shirt with a religious message to school.
August 11, 2004: ACLU of Nebraska defends church facing eviction by the city of Lincoln.
July 10, 2004: Indiana Civil Liberties Union defends the rights of a Baptist minister to preach his message on public streets.
June 3, 2004: Under pressure from the ACLU of Virginia, officials agree not to prohibit baptisms on public property in Falmouth Waterside Park in Stafford County.
May 11, 2004: After ACLU of Michigan intervened on behalf of a Christian Valedictorian, a public high school agrees to stop censoring religious yearbook entries.
July 11, 2002: ACLU supports right of Iowa students to distribute Christian literature at school.
April 17, 2002: In a victory for the Rev. Jerry Falwell and the ACLU of Virginia, a federal judge strikes down a provision of the Virginia Constitution that bans religious organizations from incorporating.
January 18, 2002: ACLU defends Christian church's right to run "anti-Santa" ads in Boston subways."
P.S.
I also don't see where you're getting the idea that "The ACLU hates George Bush".