When uploading files to your server, GoLive's helpfulness ("are you *sure* you want to overwrite this file?!" and "okay! I've uploaded the file!") can get a little old. This trick will bypass all of that, so use it at your own risk.
Step 1: Within the Site window, highlight the files you wish to upload (command or control click to select multiples).
Step 2: Control click the selected file (right click if you're on a PC), and choose Publish Server > Upload Selection from the contextual pop-out menu. Presto! You've bypassed all kinds of warning messages.