As this seems to be a common question...
- Protocol. Basically 3 (4) options.
802.11a has a speed of 54Mb/s but has poor throughput and is basically used in corporate networks stateside - not recommended
802.11b has a slower speed of 11 Mb/s but is better in terms of coverage area, but is out of favour now to the much better 802.11g which promises the same coverage area but at the faster speed of 54 Mb/s. So out of the two 802.11g at roughly the same price is by far the better option.
There is a fourth but afaik it's not yet been ratified by the IEEE, SuperG which offers twice the speed of 11g (108 Mb/s). I would steer clear of it until it's ratified but it does sound promising.
- Manufacturer. Basically whatever floats your boat. I've got a Belkin and it's fine, it also performs well in magazine group tests. D-Link, Linksys etc are also pretty decent, everyone will have their own recommendations (so please add!). If you want an ad-hoc network (no access point or router) make sure you use cards from the same manufacturer as incompatibilities may (but in theory shouldn't) cause problems. With infrastructure networks (WITH router or access point) this is much less of a problem but you'll still get better performance with the same manufacturer. The Belkin set is also extremely easy to set up.
- Wireless Lan Adapters- basically you'll need one for each PC that you want to connect to your network. Most new laptops, especially those equipped with Centrino, have them built in. Even if you don't already have the facility, adapters of various interfaces (PC-card / PCMCIA, PCI, USB for example) can be purchased. A boon with buying a router is that typically four wired 10/100 ports will be included so if you want a PC close to your router to be connected wirelessly you can save buying a card. Also one final thing- coverage will be better if you avoid metal objects in the vicinity of the router or the PC- typically wires etc will have a detrimental effect on throughput and antennae that screw directly into the adapter without an extension could be replaced or avoided if this becomes a problem. An excellent site for antenna purchase is
here.
- Router v Router and Modem v Access Point.
Access Point- extends your existing LAN with no internet connection facility. Due to the relative cost only good if you have dial-up or an existing router.
Router- a single box combining an access point and a router- useful for cable and DSL connections where a modem is specific. Typically also have a firewall and wired ethernet facility as well as direct internet capability.
Router and Modem- a router combined with a modem, useful for DSL but pretty useless for cable.
- Security- This cannot be understated, there's a seperate thread on this IIRC.
This isn't a closed shop so feel free to add anything you consider useful
Mods, as this is a common question especially at the moment would it be possible to pin / sticky / whatever it's called this?