So you have Windows 8, Aptana and WAMP and want to install Pear? This is how I did it.

1. In Explorer go to your PHP folder, mine is E:\wamp\bin\php\php5.3.13
2. Create a folder called PEAR
3. Download the file go-pear.phar from http://pear.php.net/go-pear.phar and drop it into the folder
4. Open up a command line (hit the Start key, type cmd and press enter)
5. Navigate to your PHP dir (same as above)
6. Type

7. php -d phar.require_hash=0 PEAR/go-pear.phar

8. and press enter
9. Now we need to add the environment variable
10. Open Control Panel (go to the desktop, press Start + C, hit Control Panel)
11. Go to System Security -> System
12. On the left hit Advanced system settings
13. Hit the Environment variables button at the bottom
14. Double click the Path Value and add your PHP directory as above
15. Open a new cmd prompt and type pear for a list of commands
16. Done!