sharepoint documents

It looks like it should do what you want.
Have a look at this link.

http://technet.microsoft.com/en-us/library/dd277864.aspx

Below is the series of suggestions for a similar problem by another SharePoint Admin.

The first comment is not so relevant to you but the other comments seem to explain how to move the data files to another drive.

It's worth looking into also

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Have you check all of the database files are in E drive? Since there are configuraton, index and content databases of WSS 3. Perhaps the content database is on C drive?

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You should be able to move the data file to another drive as long as it handles by SQL server since WSS only talk to SQL server, and then SQL Server retrieve data from databases
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I would agree with cobrachen -- I would also search for log files (specifically IIS and SharePoint ones) those puppies can take up alot of space if you do not have a process to clean them up. I know by default that IIS will put it's log files on the C: under the Windows folder.
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Liebrand is correct. By default the IIS logfiles and the SharePoint logfiles both reside on the c: drive.

In order to move the SharePoint logfiles, you need to go to:

Central Administration > Operations > Diagnostic Logging

and change the path of the log files from there.

In order to move the IIS log files, you need to go to the properties of the web site in IIS and on the web site tab go to properties under enable logging and enter a different path where it says log file directory.

I took an interest in this because I'm going to be required to do the same thing in a few months time....but mine will be to move it to a new server...basically the same thing though.
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WSS 3.0 uses Microsoft SQL Embedded Edition (MSEE) for its data store. When MSEE is installed, the data files are installed to your C: drive by default. Since you do not want to have a file on your system drive that can grow exponentially, you need to move it to another drive. Here is how you do it.

Note: While completing this process your WSS site will be offline to your users.

Shutdown all Windows Sharepoint services & IIS Admin service: This will ensure that there are no locks on the files you need to move.
Open a cmd prompt and cd to C:\Program Files\Microsoft SQL Server\90\Tools\binn
Enter sqlcmd -S \\.\pipe\mssql$microsoft##ssee\sql\query -E: This starts the Microsoft SQL Server 2005 Command Line Query Utility
Enter the following commands to view the available databases & hit Enter after each:
SELECT name from sysdatabases
GO
You should see a number of DBs, move the following 4 databases (GUID?s may be different):

SharePoint_Config_c464b7ce-59ef-4820-9f75-f46a0937c08e
SharePoint_AdminContent_451452bf-9dc0-40c9-be18-14f14bc23007
WSS_Search_NETSERVER_86a140c5958d4a5d97c8c2cbee745424
WSS_Content
Enter the following commands & hit Enter after each line. Repeat for each database.
EXEC sp_detach_db @dbname = ?Content_Database_name?

GO
Move the databases to their new location. They can be found in C:\Windows\SSQL\Data\.mdf and _log.ldf
After the files have been moved run the following commands (Make sure to change the itialic sections to your specifics):
EXEC sp_attach_db @dbname = ?Content_Database_name?, @filename1 = ?drive:\path\Data\.mdf?, @filename2 = ?drive:\path\Data \_log.ldf?
Go
Repeat step 7 for each database you moved.
Restart IIS Admin services and all Windows Sharepoint services
Ensure your Sharepoint site is working
If this is done before you build your site it will take no time at all to move the DBs to the new location.