Hi Priscilla,
A FIS is simply a flight information service which is given without the use of radar derived information. You pass traffic information on other aicraft that you know are in the general area. Other info which you consider pertinent such as weather reports from other aircraft etc, can also be passed at your disgression.
Fis is only provided outside controlled airspace. The only other type of service a VFR will get outside controlled airspace is a RIS (radar information service). Similar to a FIS except you can use radar derived information to pass traffic information, etc. No avoiding action will be given for either service.
Inside controlled airspace all VFRs are under a control service, wither its a radar control or an approach control service.
As in your case, all aircraft on frequency are automatically provided with an alerting service.
Hope this has been of some help and I'm sure more people will add in their tuppence worth for bits I've probably missed out.
Babe