I saw the topic Sergey made but i didn't see anything about the .htaccess method:
if you don't have access to your php.ini file you could do the same thing using a .htaccess file like:
create a new file named .htaccess in which your write:
RewriteEngine On
php_value post_max_size 10M
php_value upload_max_filesize 10M
php_value max_execution_time 60000
the above example sets the maximum file size upload to 10M and to a sufficient time to execute the upload.
please note: you need the Rewrite Module from Apache
