If you are using the netbook remix edition of the Ubuntu 10.10 Maverick Meerkat, then by default you can see the 'Files & Folders' icon in the dock bar, which will display the files inside your home directory only. So if you need to mount other partitions, you can use bash if you are a power user. But if you want our good old simple file browser, then what you need to do is:
1. Open the trash.
2. Trash is opened in the file browser.
3. Now the 'File Browser' icon appears in the dock.
4. Right-click the 'File Browser' icon and choose 'Keep in Launcher'.