Here are a couple examples to help you with uploading in PHP..

Open your .htaccess file or create one in a txt editor now. Add the below to the bottom of your .htaccess:

php_value upload_max_filesize 20M  //Add your max upload size here
php_value post_max_size 20M //this sets the filesize limit while using POST in your form

For those of you with sluggish servers, shared hosting or large files, it may benefit you to up the maximum execution time so that the upload doesn’t timeout during the process

php_value max_execution_time 200
php_value max_input_time 200

That’s a wrap, there are plenty of other resources available on php and .htaccess, just google it.