If you use the "+" sign method mentioned in the article above, you can easily determine who put your email address on the spam list. And all you need to do is to setup a filter to block that email address you used.
Also, you own "yourusername@googlemail.com" as well. For example, if your email address is "blah@gmail.com", emails send to "blah@googlemail.com" will be directed to your mailbox.