Excel -- breaking data in one cell to multiple

My "help" feature in not working correctly so here's my question:

I am trying to take multiple email addresses in one cell and put it in separate cells in 1 column. Can someone tell me how to do this? Also what is the command to remove spaces in front of first character of data in each cell? What is command to add a character such as comma at the end of each address in each cell?

Thanks in advance!!