How do I check my storage usage/limit in Sharepoint 2010?

Note: You must be logged in as an Administrator or have been granted the "View Web Analytics Data" permission in the root site of your site collection.

1. Select Site Actions > Site Settings
2. On the Site Settings page under the Site Actions heading, select Site Collection Web Analytics Reports
3. From the quick launch menu on the left, select Storage Usage under the Inventory heading to view current and historical information about your storage quota and usage.