to remove an rpm it's rpm -e rpmfilename up until you get to the .noarch or .i386
eg. a file called something.1.2.3.noarch.rpm
to remove the file its rpm -e something.1.2.3
i never used to understand what people were talking about when they'd say just use rpm -e , untill someone pointed out that you leave out the last bit

hope that helps
cheers