Need help with getmail and filtering my Mail

[iob]

i got a problem i cannot find a howto for currently i have getmail polly my 4 pop3 accounts and deliver mail into a subfolder maildir for each account which are accessed via my courier imap.

I want to add a spam filter to the process, i figured out that either procmail or dropmail would do the job, but it is very hard to understand how to configure if you leave the howto tracks.

Additionally, if i let procmail filter my mail, it will put it all into one default folder instead of the folders per account where getmail put em in. Is there some way getmail can tell the filtering application what the"default"folder for that mail is when it passes the mail through to a filtering application?

Some help would be appreciated what programs i need and how i can get my 4 pop3 boxes normal email into the 4 maildirs and the spam into the spam maildir.