Device support under Linux is excellent. No, really. The sheer number of things that will work "out of the box" without you having to search for and install drivers is impressive and, quite frankly, beats your old OS. That doesn't mean all is rosy, however. Let me be brutally honest here. Some devices have been written to work with Windows and only Windows . . . or so it seems. One of the great things about this open source world is that developers are constantly working to write drivers to make it possible to run that faster-than-light communications card.
That said, if you haven't already bought that new gadget, there are a couple of things that you should do. For starters, if you are in the store looking at that new printer, pull the salesperson aside and ask whether it runs with Linux. If the person doesn't know (which is sometimes a problem but less so as time goes on), take a few minutes to check out the excellent Hardware HOWTO document. You can always find the latest version by surfing on over to the LDP's Linux Hardware Compatibility HOWTO page:
If you don't find what you are looking for there, check out the hardware compatibility guide on your Linux vendor's site.
Red Hat's hardware compatibility guide is worth the visit, regardless of what version of Linux you are running. The URL follows. However, keep in mind that things do change on Web sites. If you don't find it there, just go to the main Red Hat site at http://www.redhat.com and look for hardware.
Here's a hint. Once there, use the Quick Search option for a fast keyword search.
Although Linux is Linux, different releases of different vendors' products may be at different levels of development. Consequently, at one time or another, Red Hat may have slightly more extensive support for hardware than the others, and a month later SuSE may have the widest range of support.
As Linux gains in popularity, you'll find that hardware vendors are increasingly interested in tapping into this ever-growing market. I've had the experience of being on site, adding hardware to a customer's system (Ethernet cards come immediately to mind), and finding that the system did not have the drivers. I quickly visited the Ethernet card manufacturer's Web site and found precompiled drivers ready and waiting for me.