Put maps on your SD card (Lumia WP8)
This is a common complaint so thought I'd post.
You can now store maps on your SD card if you have a Lumia WP8 (with an SD slot) and the portico firmware: there's an app in Nokia Beta Labs which lets you move maps to the SD card. It's called Storage Check:
You just need to register your Nokia account and phone to the service.
Verified it working on my 620. You need to have the SD card in before you start the app too.