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 (http://www.amazon.com/F5D7050-Wireless-802-11g-Network-Adapter/dp/B0002HA7FY/ref=sr_1_2?ie=UTF8&s=pc&qid=1246052907&sr=1-2)
PCMCIA attached adapter (http://www.amazon.com/Belkin-N-Wireless-Notebook-Card/dp/B001HA20CS/ref=sr_1_3?ie=UTF8&s=pc&qid=1246052882&sr=1-3)

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

Hope this helps,
WallyH