With the Slidelive service, you can instantly share your PowerPoint presentations by uploading them to the web then inviting others to a live walkthrough. Once the other participants are logged in, they can follow the slides in their browser as you clickthrough them. This could be really useful for a conference call when you also want to share a slideshow you have created.
The service lets you upload and store up to five presentations and you can manage and schedule them from your Slidelive account. Presentations can be shared with up to 100 people simultaneously. You can also keep a history of the presentations you have seen. Check out Slidelive's free service here if you want to try it out for yourself. (via)