Home network – can share using ethernet but not wireless

I have a home network where I’ve added and removed various machines over time and usually don’t have problems with sharing files and printers over the network. I’m using a Linksys router. The 2 machines I’m currently running use XP Pro and XP Home. When I have them connected to the router via ethernet, I can share files and the printer without a problem. I use the laptop most often and I do use that one wirelessly sometimes. But, when I do, the computers can’t see each other, and therefore can’t share files or the printer. I have confirmed that my wireless connection is attached to my own router and not someone else’s in the area. Is there a setting on my wireless nic that I need to make or a setting on my router? Thanks!