Andy R...you can search for contractors at the top of the page...the "everything" tag is pull down menu.
Oh word? See I need a unit recommendation...
Andy there are several contractors listed, but not knowing what your needs are makes it difficult to determine what to recommend. If you own the home, you may want to get a home energy audit performed before you decide on a contractor or system. There are several programs that go beyond the rebates that most of the AC contractors offer. A BPI home energy audit professional can help you decide exactly what your needs are and what system should be considered. Quite often with a little extra air sealing and insulation improvements, you will find that your system requirements will be much less so you not only save money because of only needing a smaller unit, but the energy savings will more then pay for the system in only a few short years.
The only other advice I can provide is the quality of the installer for the system. Most AC systems today are made with some pretty good manufacturing methods. Meaning they are all about the same. Sure some that cost more will have better efficiency ratings and some will be more quite then others, but you can get the most expensive system made and have someone who does not do the install correctly and it will turn out to be the biggest piece of junk you ever bought. The quality of the install is very important. So be sure to look into experience of the contractor doing the job.