I haven't done it, but there is one MS paint and one 3rd party paint app. Both of them are looking very nice, especially the 3rs party one can produce professional results.
I am reluctent to do it because I dont want to setup the account, the same Win98/XP case where I dont want to login to Hotmail when I login to my machine. I have to try it again and see if I can login as local account and login to store manually and logout when I close the store.
Available on Windows Phone Store is a term I am more concerned with, when company said they have an app for the device. Windows Store is short, so, it is not bad.