Here I've adapted MyDD's wonderful timeline of what to expect on election night. I took out some of his speculation to make it more readable, but included a few important notes he makes -- namely around the 9 PM time-slot, which he notes would be the earliest point at which the election could be called. 11 PM, however, he believes is the latest timeline.
7:00pm EST/ 4PM PST:
Blue States Closing: Vermont (3 EVs)
Red States Closing: South Carolina, Kentucky (16 EVs)
Swing States Closing: Virginia, Indiana, Georgia (39 EVs)
7:30PM EST/ 4:30PM PST
Blue States Closing: None
Red States Closing: None
Swing States Closing: West Virginia, Ohio (25 EVs)
8:00PM EST/ 5:00PM PST
Blue States Closing: Connecticut, Delaware, Washington, DC, Maine, Maryland, Massachusetts, New Jersey, Illinois (79 EVs)
Red States Closing: Alabama, Mississippi, Tennessee, Oklahoma (33 EVs)
Swing States Closing: Pennsylvania, Missouri, Florida, New Hampshire (63 EVs)
8:30PM EST/ 5:30PM PST
Blue States Closing: None
Red States Closing: Arkansas (6 EVs)
Swing States Closing: North Carolina (15 EVs)
9:00PM EST/ 6:00PM PST
Blue States Closing: New York, Rhode Island, Michigan, Minnesota, Wisconsin (72 EVs)
Red States Closing: Kansas, Louisiana, Arizona, Nebraska, South Dakota, Texas, Wyoming (70 EVs)
Swing States Closing: Colorado, New Mexico (14 EVs)
"9:00 is about the earliest they could officially call the election, though of course, once Obama gets to 215 EVs or so, we'll know it's ours as soon as California closes. But to repeat, the earliest victory we can hope for is here, with Obama winning:
Maine, New Hampshire, Vermont, Connecticut, Massachussetts, Rhode Island, New York, Pennsylvania, Maryland, DC, Virginia, North Carolina, Florida, Michigan, Ohio, Minnesota, Wisconsin, Illinois, Indiana, and Missouri. However, I think it's very unlikely that North Carolina, Missouri, and Indiana would be ready to call here, even if they all came up Blue."
10:00PM EST/ 7:00PM PST
Blue States Closing: Iowa (7 EVs)
Red States Closing: Utah (5 EVs)
Swing States Closing: Nevada, Montana (7 EVs)
11:00PM EST/ 8:00PM PST
Blue States Closing: California, Oregon, Washington, Hawai'i (73 EVs)
Red States Closing: Idaho (4 EVs)
Swing States Closing: North Dakota (3 EVs)
"It's time for a call from the Associated Press, if we haven't gotten it already."
12:00 AM EST/ 9:00PM PST
No closings
"I said after midnight. But look for the last few swing states to come in around now, if they come in overnight."
1:00 AM EST/ 10:00PM PST
Red States Closing: Alaska (3 EVs)