I have an older series ibm laptop. My apartment building has a wireless system. How do I get access?

You can use either a USB or a PCMCIA connection. There are many brands available, but here are a couple of links for Belkin devices just to give you an idea.

USB attached adapter
PCMCIA attached adapter

The important thing is to determine what type connections your computer has available.

Hope this helps,
WallyH