Welcome to TS, Albert.
I have a wired and wireless network running at home, off a D-Link Dl-614+ router. While most of the network is wired, the Powerbook (an 800MHz Ti) and the iMac (266MHz blueberry) are wireless or sometimes wireless. The Powerbook is running Panther, the iMac is running OS 9.1. I'm using a Belkin F5D6050 USB adapter on the iMac, which works, with one caveat. You cannot start the iMac up with the adapter plugged in - it freezes the iMac. No amount of fiddling has resolved this and Belkin sent a replacement, which had the same problem. So, we simply don't start up with it plugged in.
Presumably, other models may work better, but this one was inexpensive ($29, refurbed unit straight from Belkin) and this machine is primarily used by my 8 year old, who is not as web-dependent as the rest of us! The Powerbook has an Airport card.
The D-Link router has better range than my original snow Airport base station - don't know how it would compare to the newer Airport base stations. The Apple base stations are expensive however and I don't think they have as many ports as other routers, if part of your network is hardwired, meaning that you may have to add an ethernet hub.
Adding a wireless card to your PC should be easy. There are lots of cards out there to choose from. For Macs, Proxim has a number of Mac OS 9 compatible products:
Proxim Belkin also has a Mac-compatible (OS 8.6 and up) card:
Belkin Wireless PCIUnfortunately, the Mac-compatible cards are a heck of a lot more expensive than the PC ones...and there are nowhere near as many of them.
As for speed - you won't get the same speed with a wireless network as you would with a wired one. When I'm just browsing the web on the Powerbook, wireless is fine. If I'm doing a major backup over the network, or transferring a bunch of large files, I plug in that ethernet cable! The difference is definitely noticeable if you're dealing with large files. Depending on your house layout & construction and the location of your base station, speed can vary in different places in the house too. And until you set the network up, you won't know how well (speedy) it will all be. In my house, the router lives in our computer room. The two rooms I'm most likely to take the Powerbook to are also the two rooms with the worst reception. Figures.
Printing wirelessly is another whole ball of wax. (I've had continuing problems with it, but that just may be me and my set up) You might want to investigate a router with a print server, though check carefully on Mac compatibility for the print server part. I know of at least one (the D-Link, I think) that only works wirelessly with Postscript (laser) printers on Macs.
If you can, I'd go with a mix of wired and wireless. If possible, hardwire your most frequently used, crucial non-portable machines.
And whatever you do, don't go buying ethernet (CAT 5) cables at some place like CompUSA, or any of the big box stores!!! They charge an arm and a leg for them. There are lots of online suppliers that specialize in various types of cables and have MUCH MUCH better prices.