I would like to give a powerpoint presentation to someone over the
internet...what are my options?
Basically, I would like to control the slides while the other person is
watching it.
While PowerPoint allows you to save a presentation as website (HTML), you
cannot control what they see, because that enables them to browse through
the presentation on their own.
To show them a presentation you should have a look a Microsoft Live Meeting,
a software to make webcasts. There you can invite 2 to 1000+ participants
and show them your presentation, documents, etc. (The program is free, but
you need to pay for a server that hosts your meeting and your documents. On
Microsoft's website you find free trial offers.)
Best regards,
Ute