I've got EFISce from NavTech Software.
http://www.navsoft.co.uk
There is lots of shareware and even freeware about, but to be honest EFIS is the best I've seen, though it does cost about £69. Its not of course a primary means of navigation, but you can create routes with multiple sectors, which most other software wont do. You can enter variable winds for different altitudes and set up different aircraft with their differing weight and balance, fuel consumption, cruise speed etc. It will tell you the time on route total fuel used. You can even link it to a GPS. You can calculate all the vaiiables for the trip and it even displays a weight and balance envelope!
It has a very comprehensive database of UK and European airfields, NDBs and VORs
You could also try the following for general software Pocket PC.
http://www.ipilot.com
Trouble is alot of the software is American made and not necessarily suitable for the UK.