TortoiseSVN is a popular extension to Windows File Explorer that is used to work with Subversion repositories and working copies. The closest alternative to TortoiseSVN in Linux is RabbitVCS. It is pretty easy to install and use it on Ubuntu:
[code lang=bash] $ sudo add-apt-repository ppa:rabbitvcs/ppa $ sudo apt-get update
* Install the RabbitVCS extension to your Nautilus: [code lang=bash] $ sudo apt-get install rabbitvcs-nautilus3
Directories that hold SVN repositories should now have icon overlays on them in Nautilus. Right-click on any working copy and use the RabbitVCS SVN option to perform all the usual SVN operations on it. The GUI is similar to that in TortoiseSVN.
Tried with: RabbitVCS 0.15.3, Nautilus 3.4.2 and Ubuntu 12.04 LTS