Sure, you can cd /wherever/your/program/lies, then run ./program_name, but thats lame!
I just installed PEAR and PECL in work, and it went int /usr/local/pear. Pear itself was in /usr/local/pear/bin, so thats the path we need to add.
From your terminal:
cd ~ nano .profile
Once Nano opens (or vi, emacs, whatever you like using as your command line text editor), add the following, and thats it!
As you can see, you can add several paths in the one line, just separate them by a :
Remember to quit and reload your terminal!