TortoiseSVN The coolest Interface to (Sub)Version Control

Right-click on a folder, choose properties from the context menu, then switch to the Subversion tab in the properties dialog. The svn:ignore property contains a list of ignored files in that directory.

There's also a configuration in the settings dialog where you can set ignore patterns.

And last but not least, Subversion itself uses a config file for ignoring files.
You can edit the Subversion config file
(Settings->General->Subversion configuration file->Edit).

You will find a line in there:
[miscellany]
global-ignores = *.o *.lo *.la #*# .*.rej *.rej .*~ *~ .#* .DS_Store

Subversion creates this config file when first used.