If you are new to Vista the changes in terminology may be confusing. It seems unlikely that you are unable to connect to a normal unsecured point when able to access secured.
If you are talking about 'Cloud' and similar public wireless systems, usually you have to sign in and use their proxy.
Some such providers (I'm thinking of MacDonalds burger joints in the UK) issue a leaflet or have a staff member assigned to helping users. Personally -- and I have years of experience with wireless networking -- I found the Cloud system confusing on a Win XP laptop but it should be simpler on a Vista system.
Many hotels use Boingo and I think you may need to download Boingo's software to use them.
Public systems that require you to sign in or secured systems that require password access arre no problem what so ever. However networks that are unsecured and do no require you to sign in like in many public locations and in my house for example I cannot connect to. I don't beleive it is a problem of me not understanding how to connect. The computer notifies you that it is connected to the internet with limited connectivity, which means that I beleive it have found the network but will not allow you to use it.