How do I burn/convert avi file to burn onto a DVD disc?

I download tv/movies from frostwire(mostly avi files some mp4 for iphone), and getting a new laptop w/ 8x Dvd +/-dbl layer. What i want to know is.. 1. Is the 8x double layer the only way to burn a file onto a dvd disc so it can play on a dvd/xbox? 2. Do i need extra software to convert the avi file to another... show more I download tv/movies from frostwire(mostly avi files some mp4 for iphone), and getting a new laptop w/ 8x Dvd +/-dbl layer. What i want to know is..
1. Is the 8x double layer the only way to burn a file onto a dvd disc so it can play on a dvd/xbox?
2. Do i need extra software to convert the avi file to another file that can be written onto a dvd disc.or will the RoxioCreator software that comes with a Dell be fine?
3. What disc are used to be written on, DVD dual layer/double etc.?
4. What format is written onto the Dvd Disc, avi to ??? etc?

Hope thats enough info. the computer specs shouldn't matter just the dvd optical drive specs(8x dvd/cd +/-).
Update: Adam horrible answer, theres no details in it, id also prefer details to whatever software is recommended to me, but thanks anyways
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