The bad news is if you use Google Maps - SSL API you will still sometimes get the Secure and Unsecured alert. Here is why:
Google url above displays everything under https:// to correctly display the under secured environment. However and this is a huge however issue Google now displays a picture of the building or location off to the left without https thus giving us the unsecured error we hate to get in a secured environment.
Here is a good example...take a look at the following:
https://maps-api-ssl.google.com/maps?q=1000+Ballpark+Way,+Arlington,+TX&hl=en&sll=37.0625,-95.677068&sspn=49.310476,101.425781&vpsrc=0&hnear=1000+Ballpark+Way,+Arlington,+Texas+76011&t=m&z=17
Now using Firefox or browser of your choice, right-click on the building image Info or Image Properties... and WOW! You will see that this image is causing your unsecured error when everything according to Google should be all secured behind the Google https://
The building and location images are not listed under https:// .... you will still get an error!
Check it out for yourself and you'll see what I'm seeing... so viewing Google maps behind SSL is still an issue unless someone knows of a work-a-round to get those location or building images removed or to be displayed behind https:// and not http:// such as the case below with the image itself.
Bottom line is... this is still an issue because of the photo images are not behind SSL...
Test it and you will see what I am talking about.
If anyone knows of a work-a-round for this, I'd sure like to know. Google if you have an explanation for this please let us know.