Log Me In and Slideshare.net
Sadly, during our Ministers presentation at SSAT, we were not able to see his presentation due to a corrupt USB drive. I was saddened that no-one in his support team had shown him one of the many remote services. He are two FREE solutions;
LogMeIn offering a quick, no-hassle set up to remotely control your computer from the comfort of any web browser. LogMein has Free and Pro accounts, with the pro account adding more features to the service, including drag-and-drop file transfer, file sync, and meeting tools.
There are a number of other remote access solutions, there Remote Desktop Connection in WIndows and uNVC for example.
OR upload your Powerpoint to a hosting services, available for download by delegates, students or not, its your choice, but always there as a backup. Slideshare and Authorstream (which I blogged about previously). Or use an online Office solution.
There are other options, but thats more than enough.