The IIS7 module will let you redirect.
<rewrite>
<rules>
<rule name="Redirect HTTP to HTTPS" stopProcessing="true">
<match url="(.*)"/>
<conditions>
<add input="{HTTPS}" pattern="^OFF$"/>
</conditions>
<action type="Redirect" url="https://{HTTP_HOST}/{R:1}" redirectType="SeeOther"/>
</rule>
</rules>
</rewrite>