Changing from AS 2.0 to AS 3.0?

I have a project, a large project. I want to convert the file from 2.0 to 3.0. I am not talking about the language part, i want to change the project to accept 3.0.

When i started this project a month back and opened the main file i chose to work in 2.0. So is there a way to change it to 3.0? I tried running a 3.0 script in 2.0 and got a large number of errors. Sorry if this is an easy answer, but thanks for any help.

So the code is in 2.0 now, but you want to accept 3.0 code? 2.0 and 3.0 are about as similar as PHP and Perl, while they do a lot of similar things the syntax and approach is quite different.

So as far as converting your current code to 3.0, its not really something that can be done in a one click situation. They cannot be mixed either, a file is either 2.0 or 3.0. I did see something the other day that allows you to kind of 'wrap' two swf files, one 2.0 and one 3.0, and they could talk somehow, but that sounds kind of nasty.
http://www.flashextensions.com/products/flashinterface/examples/01_flashinterface_avms.html

If you write 2.0 code, go to Publish settings and make sure its AS2. If 3.0, make sure the setting is AS3. It doesn't autodetect either, unforunately. I hope the project works out for you, but I would suggest keeping AS2 and converting the AS3 to AS2, if your project is far along.