There's a specific tool for that in Illustrator, and it's fairly easy to figure out -- just draw out the path, or create a circle, select the tool, click on the path and voila, you should be able to type on it. As for Photoshop, the Create Warped Text seems to work okay if you fiddle with the settings enough. Simply type out the text, go to the top toolbar where you see the T on a bent path (with three dots) icon, click that, and fiddle with the settings under the Arc style option. There might be better ways, but I have old version of both programs and don't know them. Hope this helps! :)