Liveries

This should help, read it over slowly.

Or try this one.
http://www.simviation.com/lair/Repaint2002.htm

Reply so I can move this to the aircraft forum.

Is flightsim a free site?

Yes and no.
If you want a membership it's $30 a year, but they will let you in free when they aren't busy and you will get the slow servers not the high speed ones.
I looked there for your DC-3.

Just to add what Radarman has already told you - I find that Avsim have probably a better selection of default textures.
Quickest way to do it is to go into the Avsim site - (it's free to register)click on File Library (top left of page) and the library search engine page appears.
In the 'Search for' box - enter 'default and the a/c you want a livery for' OR if it is not for a default a/c then enter the name of the a/c you want.
In the 'In Category box - click for the drop down menu and choose 'FS2004 Aircraft Textures and Modifications', I assume that it is for FS2004 - Click Search and you'll get a paged list of all appropriate a/c and liveries. Download the zip files you want to a folder of your choice.
Unzip to a temp file.
Different paint(livery) authors have different methods of allocating the textures so follow the instructions in th readme/instruction file. In all cases of a new texture/livery the existing aircraft configuration file needs to be amended/added to - usually there are instructions how to COPY/PASTE into the existing cfg file. I am presuming the perfect world but many authors presume a high level of knowledge and often the instructions can be quite unclear/difficult to understand - you will always find someone in these forums to give you help in this.