I suggest you try education-portal.com. This site offers a large variety of on-line courses. Computer courses, finance, marketing, foreign languages, biology, web design, music lessons.... and they're FREE!
i would also look at Training Center (http://www.trainingcenter.com/)... they have lots of interactive training courses and you can learn at your own pace.
If you are looking specifically for Excel and Powerpoint training, Microsoft also offers online training courses here: http://office.microsoft.com/en-us/training/CR100654571033.aspx - they can be a convenient way for you to learn the most important tools for both products
I stumbled upon this website for live online software training. They are having various free course. Their prices for other courses are also very less than others. Very good timings full day, evening and weekend courses. Worth checking in this job market to keep your skill up to date!
Its good about you that you are willing to learn about online excel and power point.
But its better even to know about about Online Training for IT Certification which helps you to pursue your program because IT online training for IT certification is the focus of Tech Training Online. If you are an IT Pro, you know the value of having the right IT certifications! So here is the site for you where you can go through it and know the value of IT Certification.