Ok heres the ropes since you seem to be new,
There are many different types of programs out there that can accomplish what you require. These programs are called IDEs or Integrated Development Environments. Most support many different languages with various settings and tools ( code coloring, snippet, debug etc. ). There are a few different types of environments however which require you to decide what type of developer you are..
Simple/Minimal and lightweight:
-Notepad [ Self explanatory ]
-Notepad++ [ Code coloring, tools but lacks project management ]
-Intype [ light, support code coloring but lacks project management ]
-*E-text editor [ very easy to work with but has awkward project management]
Feature filled and more resouce intensive:
-*Dreamweaver [ Clean, easy and very user friendly]
-Netbeans [ Develped by Sun Microsystems, clean, easy and my personal favorite]
-Eclipse [ Extendable, supports many languages but has an awkward process to it]
-*Visual studio [ Nabeel's baby, easy to use, add $99.00 if you want php support. Another favorite of mine for large projects]
The ones marked with stars require licenses thus meaning they cost some money the rest are free. Google away : D