IE Cache Trasher deletes a file called "download cache" which can get quite big if you do not watch it. This file stores incomplete and complete downloads (the latter only if you set IE to remember your last completed downloads). It can grow to enormous proportions; mine was 119 MB the first time I checked.
What's new in IE Cache Trasher
Verison 1.2.1 makes this shareware, along with a direct download link.