Just because your printer, media player or other peripheral didn't come with Wi-Fi doesn't mean it must be forever relegated to the wired world. Wireless Ethernet converters or bridges are the quickest ways to get your peripherals working with Wi-Fi, usually 802.11g. These small, antenna-equipped devices connect to your peripheral's Ethernet port. Instead of being attached to a driver on a PC, they're configured via web browser, giving you the freedom to associate the transmitter with whatever peripheral is convenient for you.
A wireless Ethernet adapter won't break the bank. For example, the Belkin Wireless G Ethernet Bridge F5D7330 runs about $100 (all prices street). The Buffalo AirStation High Power Wireless Ethernet Converter (www.buffalotech.com) incorporates 802.11g and MIMO technology in an under-$70 package.
If you're looking to hook up a multifunction printer, you may not get full functionality when you use a wireless Ethernet adapter. Instead, look into a device like the $95 D-Link RangeBooster G Multifunction Print Server and check to see if it supports your particular printer model. If you don't need the wireless flexibility to place your device wherever you want, some peripherals may be better left hard-wired to your network.