I am using VS2008 and Resharper. Resharper creates a directory _Resharper.ProjectName. These files provide no value for source control that I am aware of and cause issues
This blog post provides a example on how to do what you want on via command line svn. http://sdesmedt.wordpress.com/2006/12/10/how-to-make-subversion-ignore-files-and-folders/
These change will be reflected in TortoiseSVN.
I believe there is a way to do it via tortoise however i don't have a windows vm accessible atm, sorry :(