A new study by the Congressional Research Service (found here) notes that more GOP senators tweet than their Democratic colleagues, and congressional Republicans are similarly technologically savvy.
The details of who's registered for Twitter, according to the study:
103 House GOP vs. 61 House Dems
21 Senate GOP vs. 18 Senate Dems
But perhaps here's a better question than the headline: Is Twitter really important enough to garner a Congressional Research Service study?