From Fox News:
In interviews conducted on Monday and Tuesday nights — immediately before the news of his victories — Santorum received the backing of 17 percent of GOP primary voters. That was well behind Romney (35 percent) and Newt Gingrich (26 percent), and slightly ahead of Ron Paul (14 percent).
In interviews conducted on Wednesday and Thursday nights — after his wins — Santorum’s support nearly doubled, which put him tied at the top with Romney for those two days at 30 percent. That’s an increase of 13 percentage points. Over the last two nights, Romney also received 30 percent, a drop of 5 points. Gingrich came in at 16 percent, down 10 points. Paul’s support held steady at 15 percent.
If you look at the full poll numbers, Romney is in first at 33 percent, followed by Santorum at 23 percent and Gingrich at 22 percent. But obviously, the important thing here is the trendline — which bodes very well for Santorum and looks particularly poor for Gingrich.