Using phpinfo(), I looked at the "Upload Max Filesize". Currently its set at 16M. How do I change this to 1GB?
Go to PHP folder, find this file php.ini and look for this line upload_max_filesize. Change it to 1024MB which stands for 1GB.
That is pretty large, why do you want to change to such a big size?
if you really need it this large... you'll need to think about using PHPs FTP functions to use for uploading as that allows resuming/etc... whereas an HTTP upload will not work, also, you'll need to change timeouts for scripts/etc...