by the way, does anyone know services which would provide you with a virtual land line number forwarded to your mobile?
How about a VoIP service?
eg: NodePhone2-Starter $5 per month gives $10 worth of call credits. Calls forwarded to your mobile cost $0.29 per minute with no flagfall charge.
http://www.internode.on.net/residential/home_phone/nodephone/pricing/
You get to choose which state and calling zone the number is in.
Unfortunately they don't yet support 1800/1300/13 numbers or multiple numbers on the same service (would need to sign up for multiple $5pm services).
I'm sure there's plenty of other ways to do this too.
Anyway, I use a NodePhone2 service for my business - means my 02 business number can follow me wherever I am around Australia (or even around the world - I was making and receiving calls while in South America earlier this year for the same cost as if I was still in Sydney).
I'm about to go interstate for a few weeks to visit family, so I'll forward my business number to my mobile and will just pay $0.29 per min for calls I receive - and nobody needs to know I'm not actually in Sydney - it's just business as usual. If I need to make calls I have a softphone and USB handset that I can use to call via my laptop ... 18c flat rate for calls Australia wide, doesn't cost me any more to call my clients even if I am interstate.
Again, there's plenty of other services like this out there - I'm just explaining what I use, to demonstrate the capability of the technology.
One word of warning: I wouldn't recommend a "cheap" VoIP service for business purposes. I have some friends who use a cheap VoIP service and I find it very difficult to talk to them on the phone, the quality of the calls is so poor. Make sure the service you use is good enough for business usage. I use NodePhone, but there are other good products out there too.