First get the URL of the KML export. When viewing your My Map, right click the ‘View in Google Earth’ link and copy the link to the
clipboard (probably something like ‘Copy Shortcut’ or ‘Copy Link
Location’ – depends on your browser’)

Now display your KML again. I have found it best to open a new Google Maps window, probably just go-to http://maps.google.com and paste in the URL copied earlier INTO the search box, and click the Search Maps button.

You should now get a display of your My Map – that doesn’t page.

This new ‘map’ remains a live copy of the original My Map, so you can continue to edit the main map and this copy will automatically update (subject to a small delay due to caching)

Furthermore it should be a functional map, so you can save it back to ‘My Maps’ – where it will be put in the ‘created by others’ section (it doesn’t know you created it anymore) – which has the benefit of being able to distinguish which is the original and which is the copy.

This also means that the map can be embedded – useful to embed the original My Map but with out paging[1]. And to the end user should barely be able to tell the difference.