PLEASE NOTE THIS WORKS WITH ALL NETWORKS! Not just Vodafone.
Copy this address into your phone's browser which gives you the software with no need of purchase. It is a Vodafone SatNav by Telmap. No signs of a trial, mine has been working since last year.
It also has traffic updates which comes in handy. This does use the internet to download the route so I recommend you have an internet package.
Phone models it supports (officially):
BlackBerry® Curve 8110 smatrphone
BlackBerry® Curve 8310 smatrphone
BlackBerry® Bold 9000 smartphone
BlackBerry® Bold 8900 smatrphone
I have not tried other models, however if you have the Blackberry 9700 or 9780, select the 9000 and it works perfectly.