1. Log in to the chip guide (Member Services->Log on)
2. Open query facility (Search->Chip Guide Query Facility)
3. In lower left (below box with all the search terms), you'll see a drop-down list. Select the person's want list you're interested in.

Alternatively, you can use the Trademaker utility (Member Services->Trade Maker) to compare YOUR want list to someone else's TRADE list to see who has chips you're looking for. This also works in reverse, so you can look for people who are wanting chips that you have in your trade list.