It's not official at this moment, but it looks about as official as something that is not official can officially appear. To quote Talking Points Memo:
• Huffington Post reports “two sources with knowledge of the decision” say Ryan is Romney’s running mate.
• NBC News reports “three different sources close to the Romney campaign indicate” Ryan is the pick.
• AP: “Republican official: Romney chooses Paul Ryan for running mate”
The TPM snippet has another entry...
A Democratic source offers this response to TPM: “Romney picking Paul Ryan is a sign that he has no balls.”
Romney picking Paul Ryan is a sign that he has no balls. The push to add Paul Ryan to the ticket is a recognition that the GOP isn’t enthusiastic about Romney. Ryan’s an ideologue who has championed an extreme agenda that alienates a lot of swing voters and key voting blocs like seniors. If Romney picks him, it will be a clear capitulation to the right wing of the Republican Party. And we know it’s a concern to House/Senate GOP candidates to have him on the ticket, because it will elevate the Ryan budget, so Romney picking him would be a signal that he’s willing to throw those concerns aside to please GOP insiders/right-wingers.
According to The Raw Story
The Democratic response the Romney’s apparent choice of the architect of the austere “Ryan budget” is perhaps best summed up by a Tweet from former Michigan governor and Current TV host Jennifer Granholm: “Just poured a glass of wine to toast the selection of Paul Ryan. Mmmm good.”
On a side note, wouldn't this be a great time, say -- Monday morning -- for Harry Reid to hold a press conference with his source who says Mitt Romney paid no taxes for 10 years?
Oh, and Congressman Ryan? How many years of your tax returns did Romney get to look through? Because we're still waiting for his.