ABC’s All My Children, the soap we watched for 25 years until we got a job with daytime hours, has always been ahead of the pack when it comes to lesbians. It introduced its first lesbian back in the ’80s and, later, Erica Kane’s daughter Bianca was the first to kiss another woman on daytime TV and now, after a few same-sex crushes, she married her lover Reese, which marked daytime’s first same-sex marriage, Prop 8 be damned, even if it was only fictional. (Sorry for that lame headline, btw.)
Update: WOW’s Jon Reiner tells us that, in fact, the first lesbian wedding on a daytime soap occurred on the now-defunct Passions when the witch Tabitha performed a symbolic wedding for Norma and Edna, whoever they are, in July of 2008. So we suppose that counts, even if it was only symbolic.