When using SharePoint it's handy to add multiple documents to a library at once.
I either use the Open in Windows Explorer feature to achieve this, or Upload Multiple Documents from the Action Menu on the Document library.
If there are meta-data columns in the library which are required to be completed, and no default value is set, SharePoint uploads the documents, but marks them as checked out, so they're not available to other users.
Checking in each document from the contextual menu on each document in the library is painful.
However, there is a better way.
First, from the Actions menu, choose Edit in Datasheet. Use this spreadsheet-like view to complete those meta-data columns
Second, from the the Site Actions button is in the top right hand corner, click Manage Content and Structure. This will let you browse the site through to your library. When you've found the library, select all the documents, then use Check In from the Actions menu to check the documents in.
Voila, one library of checked in documents!