Error installing virtualenv on Mac OS 10.6

When I try to install virtualenv on my local machine running OS 10.6.4, I get the following:

Searching for virtualenv
Reading http://pypi.python.org/simple/virtualenv/
Reading http://virtualenv.openplans.org
Best match: virtualenv 1.5.1
Downloading http://pypi.python.org/packages/source/v/virtualenv/virtualenv-1.5.1.tar.gz#md5=3daa1f449d5d2ee03099484cecb1c2b7
Processing virtualenv-1.5.1.tar.gz
Running virtualenv-1.5.1/setup.py -q bdist_egg --dist-dir /var/folders/Ej/EjJBMhPjFSWPq+RuE6ubhE+++TI/-Tmp-/easy_install-lZp_Mm/virtualenv-1.5.1/egg-dist-tmp-vC_6xR
warning: no previously-included files matching '*.*' found under directory 'docs/_templates'
Adding virtualenv 1.5.1 to easy-instal开发者_StackOverflow社区l.pth file
Installing virtualenv script to /usr/local/bin
error: /usr/local/bin: Permission denied

Any thoughts on how I can remedy the error at the end?

error: /usr/local/bin: Permission denied

Looking at my /usr/local directory, there is no /bin subdirectory. Any help would be great appreciated, thanks!

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You need to have root permission to install into /usr/local/bin. If you are using the easy_install command, do:

$ sudo easy_install virtualenv