Day one of my SharePoint 2010 adventure and I'd like to share a workaround that I've found quite helpful as I've run across some minor difficulties in deploying my solution.

After making changes to one or more web parts in my solution I'll occasionally receive the following error while trying to redeploy:
"Error occurred in deployment step 'Retract Solution': the language-neutral solution package was not found"

I have yet to discover the underlying cause of this error, but I've found the simplest solution to be to temporarily adjust the active deployment configuration of the project.  Here's what I did:

 * Right-click on the SharePoint project and choose "Properties"
 * Select the "SharePoint" tab
 * Create a new active deployment configuration selecting all of the available deployment steps except "Retract Solution" (no need to worry about the retraction steps obviously)
 * Click "OK" to return to the SharePoint properties
 * Select your new active deployment configuration from the drop-down list and save your changes.
 * Redeploy your solution
 * Don't forget to change your active deployment configuration back to the proper selection (most likely "Default")

Hopefully this will take care of your deployment error as easily as it did for me.