Adding the registered version of 30boxes calendar
When you sign up for the free registered calendars at 30boxes.com you can gain a few more features.
Once you have created a calendar there, it's easy to add your calendar to any of your workspace pages.
Here's the top left corner of your calendar page at 30boxes. Click on the "Share" menu item and choose "Add to Blog".

The next dialog gives you many choices, but you want to find the code in the
"Embed Calendar" section, as shown below.
Copy the embed code in that section, you'll need to paste it into your page later.

Now go to your workspace and edit the page where you want your calendar to appear.
Then hit the "Insert Plugin" button.

Choose the "HTML/Javascript" plugin from the PBworks Magic category.

Paste in the embed code that you copied from your 30boxes calendar.

This is a good place to chose the width of the calendar in your page.
800 is too wide for most workspace pages. I like to set them at 500.
You can always edit this later if you need to adjust it.

After you have the width set, finish the plugin and save the page.

Here is your calendar. In this case, it's Joe's calendar, but you get the idea.