If you want a thorough introduction to VLANs, I'd suggest starting with reading the
right here. If you have questions on a specific part of it, feel free to ask away. Once you understand the basics to VLANs, I think implementation will be easier to do also. I'll give a general guide to VLAN implementation, and that is to assign VLANs to different departments within the company. For example, give customer service their own VLAN, sales another, billing another, and so on and so forth. What sort of switches are looking at implementing VLANs on?
DG ... u can read the CCNA/CCNP books which covers the VLAN to an extent .... if u want to cover the VLAN's in great detail then u can go for Cisco press book on VLAN's which is available at all the good stores