Simply replace the unfilled areas such as "__" and "_[date]_" with your information.
To All Staff:
Please allow me to take this opportunity to introduce myself to all of you. My name is _[name]_, your new _[type of position]_. It is a pleasure to have joined _[name of organization]_. I consider myself fortunate to have been given this opportunity to join an organization with such a fine reputation for its _[quality products/services/etc.]_.
This _[type]_ position offers new and exciting challenges to me, all of which I am looking forward to. Prior to coming to _[name of organization]_, my background entailed_[briefly describe the field you worked in]_. The last position I held was, _[type of position]_ with _[name of organization]_. Now, I look forward to this new position where my responsibilities will include _[briefly describe position]_ and I'm quite anxious to get started with these new challenges.
I can see already that this is a fine group of people I will be working with. I'm looking forward to having an opportunity of chatting with each of you over the next while. Glad to be on board!