How to increase the execution timeout in php?

You should be able to do during runtime too using

set_time_limit(100);

http://php.net/manual/en/function.set-time-limit.php

or in your vhost-config

php_admin_value max_execution_time 10000

Having a global execution time limit that is LOW is mostly a good idea for performance-reasons on not-so-reliable applications. So you might want to only allow those scripts to run longer that absolutely have to.

p.s.: Dont forget about post_max_size and upload_max_filesize (like the first answer told allready)

You need to change some settings in your php.ini:

upload_max_filesize = 2M 
;or whatever size you want

max_execution_time = 60
; also, higher if you must - sets the maximum time in seconds

Where your PHP.ini is located depends on your system environment. For more information: http://php.net/manual/en/ini.list.php