I have found a cool online SVN service provider.
Beanstalk is a hosted Subversion system, making it easy to setup, browse, and track Subversion. Beanstalk has built-in integration with your favorite tools such as Basecamp, FogBugz, Campfire and more.
It rather impressive and it is free for limit usage. One core feature is Beanstalk allow permission setting for free user. Many of others online SVN service does not provide that. Another feature is Beanstalk create a personalize domain for your SVN project.
So for, in my test environment, it performs well and tortoiseSVN works with it perfectly.