Question: I'm hoping to restore a backup from SQL Server 2008 into a Sql Server 2005 instance. Is there a way to have Sql 2008 back up in a format that 2005 will understand?

Answer: 
Short answer:

No
--

You cannot restore to a lower major version of SQL Server. 

You can however [Generate Scripts](http://blog.sqlauthority.com/2009/07/29/sql-server-2008-copy-database-with-data-generate-t-sql-for-inserting-data-from-one-table-to-another-table/) from your database for SQL Server 2005, just choose to include data in the wizard, and then you'll just need to rebuild indices and such, once you've run the scripts on your 2005 instance
No, the formats are incompatible. In order to go backward you will need to script out your database and create it via script in the older version.

Note that you could run into incompatabilities due to new features and datatypes in SQL 2008 that weren't available in 2005.