Spambox for individual mail accounts

hello, im looking for some assistance on this, i get 3 or 4 pieces of spam in my inbox each day, i have set spam assassin to prepend "Spam: " to the subject of all emails that it deems to be spam, this helps alot when checking my emails because they stand out a bit, anyways, what i would like help with is setting up spamassassin or procmail or postfix (which ever this applies to) to send the spam mail into a junk folder in the user account instead of just laying it into the inbox. any help with this would be greatly appreciated.