Codes, Regulations, and Safety Issues
If you live in a condominium, you may need to secure permission from the association board before you begin the work. And no matter where you live, it is nearly guaranteed that you will need a building permit to replace your wall with a support beam. Verify if you need a building permit by calling your local permit office or checking online.
Ask for a consultation?
Is your support beam sufficiently sized for the opening? Consult span tables or, better yet, hire a structural engineer to determine the proper dimensions of the beam you'll be adding. A beam that is undersized for the load it carries can be a very serious problem.
Remember that plumbing or electrical services likely run through the wall. Shut off the electrical circuit breakers controlling any circuits running through the wall, and use a voltage detector to verify that the power has been shut off.
Electrical wires running through the wall will need to be addressed. Most likely there will have at least a couple of outlets and a light switch or two that you'll need to relocate. In many cases, it's a matter of moving existing wiring to a different portion of the wall or to a new wall. If you feel even the slightest bit uncomfortable with electrical work, hire an electrician.
If plumbing pipes run through the wall, shut off the water at the source before beginning work. A professional plumber may be needed to reroute or remove plumbing pipes running through the wall you want to remove.