Best linking stratergies

Hi,

I hope someone more knowledgable than me can offer me advice on linking. My query is if there are several sites all covering a similar topic which would bethe best way to link between them for maximum SE benefit and maximum traffic flow between the sites.

I do not actually have any sites I am just asking theoretically. The sites would be on different servers.

Thanks.

I hear the new "a" tag with a "href" element works well.

Search Engines:
you have 5 websites
on each you put a link to the 4 others in a box or something
as simple as that

People/traffic:
"Find more information on xyz topic, click here"
perhaps have 2 such links (top/bottom) altering between the 4 other urls with php


That's how I'd do it