3Com has a very nice tutorial on IEEE 802.11b and wireless LANs.
You will want to keep abreast of the developments in 10 Gbps Ethernet (IEEE 802.3ae).
For an overview of all the IEEE 802 standards check out this downloadable .pdf page from IEEE.
And all the Working Group Home Pages for IEEE are found here.
Cisco has a very good tutorial on switches.
IBM also has a good tutorial on LAN switches.