<<< Whats the best make to buy for the router, belkin and netgear sound like the commercial ones,I heard linkseys are the best as the are an offshoot of cisco? >>>
Any of the mainstream products should be fine - Belkin, Netgear, Linksys, D-Link etc. ADSL requires a combined "Router/ADSL Modem" which replaces the normal USB modem.
<<< Does the make of the network card have to be the same as the router? >>>
If you decide to go for one of the "speed boosted" products, with speeds above the 802.11g standard of 54Mbps, then "yes" stick to adapters from the same manufacturer. There is at present no laid down protocol for wireless kit running at speeds above the 802.11g standard. All 802.11g hardware should be compatible.
<<< I have 2 desktop pc's and a laptop (lucky me :))and i want to conect them all, im on adsl what would be the best way? >>>
A 'wired" connection will always be more reliable than "wireless" so any computers close enough to the router should be connected by ethernet cable. Only use "wireless" for remote computers.
<<< Are usb dongles any good how do they compare with normall wireless cards? >>>
USB 802.11g adapters are fine, but if using a USB 1.1 port, their speed is restricted by the 12Mbps speed of USB 1.1. To utilise their full potential, they require a USB 2.0 port (which supports 480Mbps). This isn't significant for the relatively slow speed (in networking terms) of broadband connections, but is noticeable for large file transfers between computers.