I've been having a play with the GoogleMaps API and found the .Net GoogleMaps control which makes it even simpler to add Maps to pages. The boys over at codeproject also had a nice tutorial using it.
There was also a very helpful portal site which I found various links to Geocode sites etc.
I'm hoping to get this in place for my project site for events utility very soon. The main steer here is the fact I want it to be very easy to add a marker on a worldwide map for the user rather than having to deal with longitude and latitude.  There are a few ways of doing this:
Geocode
The problem I've found is that the geocoding tools around are not worldwide and some are better at the USA and some are better at the UK. Most are based on being free unless you hit the webservice too much. I'll be okay with the hockey site with probably only a few uses a day.
Pointing
The other way of getting the information from the user is to let the user scroll around the world map and point where they want the marker. The problem here is it's not to accurate and is also a slow process for the user who has to scroll and zoom in and out. GoogleMaps also don't have overlay images for the entire world so areas like Australia and Spain are not covered making it hard to pin point areas accurately.
This can be made easier by having each country in a drop down which then moves the map to the correct zoom level and then the user has a bit of a jump start.
Manual code
The other way is to manaully ask for the code and give them different ways of getting it using off-site geocoding tools. This may be the only choice for some areas of the world for now.

It'll just be another part of the process of adding an event in the Add Event page. I'm going to make it controls based so that I can then resuse this for adding a marker for a club and so on...

UPDATE
I found a UK site which has further examples here and also the Google Map API group which is very useful for answers! I've actually canned using the .Net control because you haven't got the flexibility to hack the Javascript as you do when you manually create it.