There are many flights to Orlando at various prices.
The one thing though, August is one of the more expensive times for flight prices (something that annoys many of us), for example our Virgin fly drive price is £849 adult price.
I have never flown with anyone else, but I know that TCD (Travel City Direct) are cheaper, and possibly also the likes of First Choice also.
The one thing to be aware of is there are 2 airports, MCO Orlando International and Sanford International, SI is a good hour or so travelling time away from Orlando itself, so you would need to be careful when booking a flight that you know which airport is used.
To be honest there are many more people on these boards who know more about the different flight operators than I do, so I am sure you will get more suggestions and feedback.
As for villas, there are thousands to choose from, I presume that you will be renting a car though? you will need one if staying in a villa.
We always stay in Kissimmee which gives us easy access to restaurants/supermarkets/ plus all the attractions etc
You can view villa examples on these sites:
www.vr360homes.co.uk
www.villas2000.com
www.holiday-rentals.com
Are you buying theme park tickets before you go?