This post is old, but still relevant, so I'll try to answer it.
First, you'll need to define a custom function (not sure if all FM flavors custom functions, but FM Advanced does).
Here's a link to a site that has a function almost exactly to your specifications (nothing but the map, and the zoom/direction/map buttons): http://www.briandunning.com/cf/1085
You'll see that the HTTP code has a placeholder for "address" "city" "zip" and "zoom". You will need to replace those terms with a function (e.g, getfield) in order to pull the info entered by the user (or you can hardkey if you want a static map).
After that, set up a web viewer on your layout (name it "web"), choose "custom web address", then hit specify, then select the custom function you created. Thats it.
If you need to change the appearance of the map (from plain map to satelite imagery, for example) let me know and i'll post the relevant code for you.
I'm not sure why you need a custom function for this?
Zoom can be one more field referenced in the URL code and thus a simple script/button that modifies the zoom setting can be specified.
I use: z=14 to set the zoom level to 14 in one of my solutions. If I wanted to set the zoom via script, I'd just refer to a field here instead of the literal value 14.
Phil, Good point, you dont need a custom function. All you really need to do is put the url directly into the web address box in the Web Viewer Setup.
Not sure what utility defining as a custom function adds, other than ease of portability?
Also a good point about incorporating more fields, instead of hardkeys, to add more flexibility for the user.
Instead of a field, this can be a reference to a global variable also.
yet another good point. So many ways to do things in FM...
Here's a challenge (for me) I haven't yet started yet (bc bc I imagine it will be heavily reliant on url code/googlemaps API and I dont know a whole lot about it). Maybe you can throw some pointers my way:
Start a loop to grab each address (of e.g., apartment buildings) from my records, put the data in a $stack, set up a web viewer to call google maps, map each address, use the GPS feature of googlemaps to show my current location on the same map, exclude from the map all properties that are not X miles from me.
Any ideas on how to make that as easy as possible?