In this good Reuters opinion piece, Jonathan Wright argues that the Ikhwan’s influence in the present uprising has been greater than most observers think. He quotes Michael Collins Dunn of the Middle East Institute, who downplayed the Muslim Brotherhood’s role in the current protests by noting the paucity of beards among the demonstrators, and the fact that even those with beards also had mustaches, “not the beard-without-mustache ‘uniform’ we associate with the Muslim brothers.”
Wright responds that the Brothers come in all shapes and sizes — many clean-shaven, with suits and ties — something that conforms to my own experience. He also notes that the Brothers, from bitter experience, do not rely on street protests, do not want to spook foreign observers, and are wary of taking power on their own since they do not feel ready to govern.
For another good take on the protests and the Muslim Brotherhood, see Jeffrey Fleishman in the LA Times. Note the Brother who says that neither a Coptic Christian nor a woman can be president of Egypt.