Wrong location for sent mail

[scrappertoo]

Using Outlook 2007 on Windows XP

When I send an e-mail, my copy of the sent mail doesn't always go to my Sent Mail folder, but accumulates under my name in the folder containing the message I'm replying to.  I have it set to put copies of my sent mail in the Sent Folder.  Any clues what setting could have changed this?

Thanks.

[Spoiler]

have you looked into the set of rules you have setup?

http://office.microsoft.com/en-us/outlook/HP052428971033.aspx