from: www.wduffy.co.uk/blog/remove-address-bubble-from-google-maps-iframe/

If you cut and paste the <iframe> info from a Google map page using Customize and preview embedded map to insert an <iframe> own site, the default is to have an location icon and an address balloon. Well, many times the address balloon is blocking important info, or lays partially outside of the iframe size.  If you wish to turn this balloon off, you can.

When you paste the code into your page simply find “iwloc=A&amp;” and remove A from the value. You should be left with “iwloc=&amp;”.  You are left with the nice little location icon, but without the balloon.  If the user clicks on the location icon, they will then get the address balloon and the map will center itself around the balloon so you can read it.