I need info about buying an adaptor and installing it to connect to wireless internet. I'm moving and the manager of the new place says they offer free wireless internet. She said I just have to buy the adaptor. How does this work? Don't I need an ISP?
They are providing internet access. From there, you can surf the web, and use some email like yahoo/gmail/msn.
You should ask the manager for details.
You could ask if they prefer a particular brand, or if there is a login required, and if they have a firewall. Maybe they already have a printed handout on how to connect.
If that doesn't provide enough information, you could ask them for help. If they don't specifically offer assistance, at least you might know a little more about the setup, and come back here for more help.
It might be a lot simpler than you would expect.
At the simplest, you might need a $10 USB WiFi adapter, plug it in, and all would work. You might want a firewall on your machine to protect you from your neighbors, as well as the internet at large, depending on how they are configured.