Edit: Sliderocket is no longer free. Therefore, I have uploaded the presentation to Slideshare

SlideRocket is an online presentation tool that helps you create , manage and share your presentations. With this tool you can create better slideshows more quickly from within any browser.You can also upload your  PowerPoints or Google Docs presentations. Presentations are stored on SlideRocket’s servers and can be accessed from any device that is connected to the internet. For casual users , it’s free.