Short talks are for 30 minutes. This is a good one if you want to introduce a new concept to the audience (like CSS styling in e4 or using eGIT).
Long talks are in-depth & advanced talks for 60 minutes on a particular topic. e.g: EMF Tutorial. You are expected to cover the advanced stuff with demos
Extended talks are hands-on workshop for 120 minutes. e.g: Workshop on Xtext. You have to walk-through the subject along with your audience and make them understand the complete concept
Submit your proposals here: http://bit.ly/EclipseDayIndia2011Submissions
The last date for submitting the proposal is Feb 28th 2011, but that doesn't mean you have to wait till that date to submit your great talk. Start submitting the proposals at the earliest.