We'll have to Mega Man is also coming to Monster Hunter: World as a Palico, (essentially a companion to help you during quests), so this is no surprise.
PC availability for the skins and accompanying voices is not mentioned in Capcom's announcement, but I see no reason why this would be a console-only crossover. You'll have to complete a special quest to unlock each skin, which both male and female characters can use. On console, anyone that has a Street Fighter 5 save file will get early access to those quests, and I wouldn't be surprised if the same ends up happening on PC.
The skins are free, but if you want to Hadoken or Shoryuken it'll cost $3.99 as a ' gesture'.
Steven has played through the PS4 version and here's his piece on why people love it so much.
