For SQL access: if you're running MySQL,
http://www.mysql.com/products/workbench/ ... this will tunnel over ssh quite well, and is available for the major OSes.
For transferring files: most OSes can do SFTP out of the box, as will your Linode; I would expect a "website developer" to have their own application of choice for transferring files. Under very few circumstances is plain old FTP acceptable for use over public networks, and this isn't one of them.
Note that both of these involve GUI applications installed on the developer's machine, which connect to the server using ssh. This is a performance and security win, and since your devs can use the tools they're most familiar with, it can improve productivity too.
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