We are considering painting my son's bedroom. We live in a mobile home. All walls are white and my guess is that it's enamel. Do we need to prime or do anything special to prep? And would enamel be the best choice to paint over with?

What kind of sheen or gloss does it have?
Is it oil based or latex? You can check to see which it is with a product called GOOF OFF, which you can buy at a paint store. The GOOF OFF will soften latex but not oil based paint.

Goof off is a good product, but you can accomplish the same task with a dark colored cloth and rubbing alcohol.

Almost any surface can be painted by using a good bonding primer such as Stix Primer from Insulux (A Brunning Company). Wash first using a strong cleaner and rinse well to remove all residue, allow to dry for several hours, sand to remove the gloss, repair any nail holes or pops, prime and then paint. A kids room should be a good washable paint. I know it's pricey, but look into Benjamin Moore's Aura brand. You can't beat its ease of use and it's washability.

The Stix primer would be a good choice for a primer and you don't have to worry about if it is oil based or latex as it will stick to either. It is made by INSL-X which is a Benjamin Moore company and you should find it at stores that sell Benjamin Moore products. The Aura product is great and is the best you can find.

I have not heard of the alcohol test.

I had not heard that BM acquired Insl-X. The last I knew was that ithas been absorbed by Brunning, but all that is kind of a moot point to the topic. :o)

The alcohol test is king of an obscure test. I'm sure the makers of Goof Off would like to keep it quiet!

Happy Painting!

No, it did not need any prep. I got the job done.(I think as well as most any non-painter could claim that.) Thanks for the assistance.