First Congratulation, don't forget celebrate it with your friends and your family, before you reading this, i suggest you to read How to being a good Supervisor.

So how do you make this transition? unfortunately most companies don't offer much training when they promote someone to supervisor. They may send you to one of those one-day seminars but you want to get off on the right foot now. So what you have to do? this simple things you can do (commonly) :

• Don't let the promotion go to your head
  It's true you must have done something right to get promoted, but it doesn't suddenly make you smarter then you were yesterday and it doesn't make you better then the people you are now supervising. If you walk around with an inflated ego, everyone will notice and no one will appreciate it.
• Talk to your new direct reports
  Most likely your boss will tell them about the promotion and you might have a chance to say a few words but that will be brief and not really sufficient. You should sit everyone down within a few days of the change for, exp :

+ Group Meeting
+ Let them know you will meet with each of them individually to discuss their roles and to set down expectations as well as address concerns.
+ Ask them what they expect from you.
+ Tell them what you expect from them.
"Obviously you need to figure this out before you talk to them, but things like what they need to clear through you, how you will communicate information, how you would like to be informed of things (email, brief meeting)."
+ Individual Meeting
+ Ask them how they feel about the change, do they have any concerns, are there any outstanding issues you should know about.
+ Prior to the meeting ask to review each person's file, so you can see what they were rated in for their last performance review, if there were any discipline issues, you should discuss this during your one-on-one to make sure you get it in the open and set your expectation going forward.
+ Discuss what they are working on and set expectations or set a time for a follow up meeting to set expectations (you may not know enough to set them during this first meeting)
+ Take extra time with people you were closer with to discuss how this change will impact your friendship. Unfortunately going forward you shouldn't be having lunch with your buddies unless it is with the whole department.

If you think you can maintain an outside of work friendship, go ahead, but use caution, you don't want people accusing you of playing favorites and you have to be able to perhaps discipline your friend, and heaven forbid, terminate them.

• Set up regular meetings
  Department meetings as well as one-on-one meetings to make sure you are staying in touch and communicating effectively.
• Find a mentor
  If it isn't your direct boss then seek out someone who you consider an effective supervisor or manager and see if they will help you grow and develop in your new role.

Becoming a supervisor can be a rewarding experience and the more you are willing to ask for help and admit you don't have all the answers the better you will be. Remember to communicate with your direct reports and with your boss, keeping everyone informed will help avoid unnecessary problems and issues.

If you have the opportunity to go to training classes, make sure you go, don't say you don't have time and don't think you know it all. Even if you learn only one thing, it's more then you knew yesterday. Also, training classes give you a chance to network with other supervisors and seek out advice and support after the class is over - and that goes for internal and external classes.

Like most things, supervising people always looks easier from the outside looking in, but you can be an effective supervisor if you are willing to keep an open mind, ask for help, and realize you can always learn something...http://bit.ly/PromotedtoSupervisor