Useful Stuff:
AIP (online on the ais website, see below)
AIC (see above)
Pooleys VFR Guide (or similar)
ANO (online on the CAA website, see below)
JAR Ops-3 (online on the JAA website)
Company Operations Manual
www.ais.org.uk (free but needs registration - Notams, AIP, AIC, Flight Plan Form )
www.metoffice.com/aviation (again free but needs registration - free weather info)
www.caa.co.uk (especially in the Publications Section - ANO, FODCOMS, GASIL, MOR Scheme, ...)
www.jaa.nl (JAR-FCL2 and JAR-OPS3)
And best of all, talk to (hopefully competent) pilots with experience in the area. I find that most people are very willing to share information. Also don't be afraid to call ATC on the phone and ask them to explain local procedures' they are really quite friendly people ....