Your are going to need GIS skills, so here is the software to get you started. Free and open source: Quantum GIS.
BGS Data Downloads
UK National Data Repository
The UK National Data Repository is the site where you can download all sorts of subsurface data, including well data, 2d and 3D seismic data.
National Offshore Petroleum Information Management System (NOPIMS)
Geoscience Australia has developed the National Offshore Petroleum Information Management System (NOPIMS) as an online data discovery and delivery system for all Australian offshore petroleum wells and survey information. There is lots of data here for you to download and play with, including well data, 2D seismic and 3D seismic.
Fossil Hunting in the UK
This is a great site to help you track down those fossils in the UK. Find out where to go and how to identify your finds.
Live Lightning – Follow Those Storms!
Volcano Cams
San Andreas Fault Sensors – USGS
The USGS offer lots of live webcams and monitors. This is example is is the 66 monitors around the San Andreas fault that can be monitored live.
British Geological Survey – UK Sensors
The British Geological Survey have links to a lot of live monitors, throughout the UK. A great way to engage in the dynamics of geoscience in the UK.
British Geological Survey Apps
The British Geological Survey has a wealth of apps for you to explore the geology of the UK. Take a look at their iGeology App, also available in 3D.