In InDesign, you will want to package your files rather than sending us a *.indd.  Here are the steps to do so.

Open your file.
Open your file.
Go to the InDesign Menu, and choose "File -> Package"
Choose File -> Package
A window like this comes up. You may have some warnings like this one indicating RGB color space being a problem. Clicking on "Package" is acceptable in this case.
A window like this comes up. You may have some warnings like this one indicating RGB color space being a problem. Clicking on "Package.." is acceptable in this case.
Ignore this window and click "Continue"
Ignore this window and click "Continue"
Choose a location to save your file.
Choose a location to save your file.
InDesign will generate a folder that you should package.
InDesign will generate a folder that you can package and send to us. Compressed formats that we can use are: ZIP, StuffIt, tar.gz, or tar.bz.