Errors With htaccess non www to www redirect after upgrade to 3.0

After upgrading to 3.0 I’m encountering errors when attempting to add a redirect rule to htaccess to redirect non www to www.

Here is my htaccess after upgrade to 3.0:

RewriteEngine On
RewriteBase /

#uploaded files
RewriteRule ^(.*/)?files/$ index.php [L]
RewriteCond %{REQUEST_URI} !.*wp-content/plugins.*
RewriteRule ^(.*/)?files/(.*) wp-content/blogs.php?file=$2 [L]

# add a trailing slash to /wp-admin
RewriteCond %{REQUEST_URI} ^.*/wp-admin$
RewriteRule ^(.+)$ $1/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule . - [L]
RewriteRule  ^([_0-9a-zA-Z-]+/)?(wp-.*) $2 [L]
RewriteRule  ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]
RewriteRule . index.php [L]

<IfModule mod_security.c>
<Files async-upload.php>
SecFilterEngine Off
SecFilterScanPOST Off
</Files>
</IfModule>

and here is the rule I’m trying to add:

# BEGIN Non WWW Redirect
Options +FollowSymlinks
RewriteEngine on
rewritecond %{http_host} ^example.com [nc]
rewriterule ^(.*)$ http://www.example.com/$1 [r=301,nc]
# END Non WWW Redirect

I’ve tried adding this at the top of the other rules and at the bottom.

I’m getting essentially a “loop” after adding the redirect, such that the URL will never resolve — just bounces back and forth between “example.com” and “www.example.com” and finally (FireFox) says, “Firefox has detected that the server is redirecting the request for this address in a way that will never complete.”

Any help would be appreciated.