Apache mod rewrite help

[sixx <xyz neoscene com>]

Been stuck at this mod rewrite recipe for quite a while and was wondering if
anyone could help out.
What I hope to achieve is for www.user.host.com to be redirected to
www.host.com/~user/
The mod rewrite recipe suggested the following

RewriteEngine on
RewriteCond   %{HTTP_HOST}                 ^www\.[^.]+\.host\.com$
RewriteRule   ^(.+)                        %{HTTP_HOST}$1          [C]
RewriteRule   ^www\.([^.]+)\.host\.com(.*) /home/$1$2

But it doesn't work even I tried it out, could someone point out where's the
error ?

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