Both mike and mic commonly appear as shortened forms of microphone, but mike is the accepted spelling in most dictionaries. Mic presents difficulties because it looks like it should be pronounced mick and because it produces the problematic participles miced and micing. Miked and miking work better. Of course, however the word is spelled, it is a verb mainly in the phrase mic/mike up, meaning to put a mic on someone or something.
Properly uniformed, Cos took the mike to philosophize and amuse. [Washington Post]
Williams response was fittingly a throw back to the 90s, as he shouted “shabba!” into the mike. [Guardian]
Seemed like every time they needed someone to say something articulate at the press conference, they handed the mike to you. [USA Today]
I remain partial to my own USB studio condenser mic from Samson, which I have been using for recording interviews and making Skype calls for several years. [Boston Globe]
Back behind the mic, no sister required [Independent Online]