Esa's Google Maps API v3 examples.
An Elementary Geocoder[3]
Buttonless geocoding, third version
Just type and when you see a good suggestion, select from list.
If you click elsewhere or hit Tab or Enter, the first suggestion is selected.
More technical
Geocoding is requested by keyup event of text field.
Results are displayed as an ordered list.
Map is set to the result by 'click' on list item or 'change' event on text input.
Request is not sent if the previous request was sent less than 300ms ago.
Tip
While testing:
Two number queries like "11", "22" etc gives you many choices with less typing.