To add a pin you need the q parameter. It holds q=latitude+longitude+(url-encoded-text)
Here is an example of hybrid map with weather - pin at Embassy Suites, map centered on Horseshoe Falls
https://maps.google.com/maps?hl=en&ll=43.076,-79.074&spn=0.0212,0.0496&t=h&z=16&q=43.0795N+79.0818W+(Nice%20Hotel)&lci=weather
- hl= two letter language code
- ll= the map center using coma
separated +/- values
- spn= the viewport span in degrees, works with
the z parameter
- t= map type {m|k|h|p}
- z= is the zoom factor
- q= latitude+longitude+(url-encoded-text), the lat/lon in q have to be
followed by a letter - N/S or E/W instead of using +/-
- lci= special codes, coma separated - i know of weather, transit_comp, com.panoramio.all
- layer= additional layers, e.g. t for traffic
Google is changing things with the new Google Maps and a lot of functionality has been removed/replaced. You can check the new Maps Engine here http://mapsengine.google.com/map/