The bad part is that the plan does not include any data usage on Smartphones.
But there is a way to get this working on Android phones.
First you have to configure the Rogers APN in Android.
Then, you will get a text message redirecting you to a rogers.mobi URL where you can select a daily or weekly pass.
At the time of this writing, the day pass is $2 for 20MB, or $7 for a weekly pass with 125MB of data.
This is good for someone like me who lives and works where WiFi is always available, but needs to check email and stuff in a hurry when occasionally on the road.