Lila Shapiro: "Although six states and Washington, D.C. legalized gay marriage before Tuesday night, they did so through the votes of state legislators or court decisions. The new victory undermines the conservative premise that those early wins were merely the result of liberal bias in state legislatures and the courts, and it reflects what recent polls have shown to be a shift in Americans' views on the issue."
Source: Lila Shapiro. "Gay Marriage Victory: Voters Legalize Same-Sex Marriage In Maine and Maryland." HuffingtonPost.com. 11/07/2012.
As to when the new laws will become effective, that depends on each state.