To import data into Dynamics CRM Online you can use the import tool or the data migration manager.
See http://blogs.msdn.com/dynamicscrmonline/archive/2009/01/20/tip-for-a-successful-import-using-the-import-wizard.aspx and http://blogs.msdn.com/dynamicscrmonline/archive/2008/06/16/data-migration-with-crm-online.aspx.
These are two blogs that describe both of these tools. Both offer the ability to import your data into your system. They give you the ability to load complex and simple data sets.
With the new automatic trial process, I thought it be nice to have a simple 1-click tool to load up some sample data for trial systems and for demo purposes. This eliminates the need to have to learn one of those tools to get some data in your org to evaluate the application. Also, you can use the data for demo purposes.
I created an application CRMQuickDataImport that will create a dozen or so contacts and accounts to populate your CRM Online trial or demo organization. When you done with the data, you can simple delete the accounts and contacts , and then load up your own data. I created a short video that shows how to use the tool.
It's pretty simple. Download the zip file. Unzip/Extract to a directory. Run the CRMQuickDataImport.exe. Enter you org name, user id and password. Press Enter. Done. Data is loaded and you can use immediately.
If you skip the video, and download first a tip is that you'll need to use the organization name when logging in.
Example URL - https://AcmeCRM.crm.dynamics.com
Then the org name to use logging in is AcmeCRM