Netgear, Siemens, Linksys, and a couple other manufacturers make DSL/Cable routers with both 10/100 wired (usually 3-4 ports) and 802.11b wireless.
The routers support NAT so multiple PCs can share the one WAN connection transparently - they also keep the DSL/cable link up whether your PCs are on or not, so when you turn on your PC you don't have to wait for the DSL to connect. The routers are usually configured/managed via your browser and most also support DHCP for convenience on your internal LAN.
Note that the use of NAT in the router effectively walls off your internal LAN from outside hackers, which is nice unless you're doing anything that needs the ability to receive unsolicited inbound connections for some reason (most don't) - you won't be able to do that through this type of router.
However, if you need to be able to connect to and control your machines from a remote site, check out GoToMyPC.com - I've been using it for about a year, it's fairly cheap and it works great and you can establish a secure link from the outside to your home machines even if you're using a NAT router.
The hardwire/wireless combo routers give you the option to connect one or more machines on wireless if you can't or don't want to run Cat 5 cables to them. You use a PCI or USB based wireless adapter on the PCs you want to connect wirelessly. Most support encrypted communications if you're worried about the neighbor kid hacking your wireless LAN.
Check Circuit City (I was there last week and both the wireless enabled routers and the adapters were on sale) or online.