Regards setting up an AWIB on VHF. I was previously involved in managing an airport that found this service of great value to its users i.e the pilots. The initial service was the same as what you say exists at your airport now - the telephone. Many positive comments were passed to me following the implementation of the AWIB. It also saved ground operators a lot of time in radio transmissions to their respective RPT crew.
The cost is obviously a factor, as previously mentioned in another reply. The BOM set the service up at the airport I was involved in at a cost of appproximately $7000, so if the traffic is high enough at the airport you are operating from, then it is very much worth the expenditure.
Unfortunately, though, too many pilots criticise the airports and the airport operators for not providing the things that they want and expect. Please though, try and convince the airport operators that this is a very valuable source of information. Good luck.