As someone who's always on the lookout for ways to save money, I was pleased this week to come across a way to potentially shave some dollars off my phone bill - VoIP over 3G.

I've been a user of VoIP (Voice over IP) services for years and have enjoyed the way they've been able to get my fixed-line phone costs down to something that doesn't induce a nose bleed every time a new bill arrives.

I'd also toyed at times with using a VoIP client on my mobile phone, connecting via a WiFi network and avoiding the mobile network altogether. But while this works reasonable well on my home office wireless network, it was often problem plagued out in the real world.

Mobile VoIP quality was often patchy and the log-in requirements needed to access many public WiFi networks meant it was often just easier to make calls in the regular way.

But now the plummeting price of mobile data is changing things all over again. Where once you had to pay around $100 for a gigabyte of data, now the same can be had for around $15. With market competition rising, these costs are likely to fall even further.

So the question becomes, why not use that data for making VoIP calls? According to the chief executive of smartphone applications company Big Tin Can, David Keane, you can squeeze around 500 minutes of voice calls out of 1GB of data allowance. That equates to a call cost of 3 cents per minute - pretty attractive really!

Keane predicts we'll see a flood of calls away from traditional mobile connections and onto mobile data during the next 12 months.

That's not good news for the carriers, but certainly puts a smile on my face!