If you created the character on single player you will only be able to play that character online using the 'other multiplayer' options which is either open battle.net (not recommended because of the large amount of hacks there) or through TCP/IP. TCP/IP we do on occasion on this forum and there is a MP subforum in the single player forum specifically for these types of games.
If you want to play on the normal multiplayer mode through battle.net you will have to reroll your character, the characters created there are stored on the battle.net servers and are more secure than the open batttle.net counterpart.
Originally Posted by Vivi
Give a man a fire and he's warm for a day. Set him on fire and he's warm for the rest of his life.