hi - I'm an experienced web dev but I wanted to get opinions on any good solutions for this:

I need to put 5 decision tree flowcharts on a site

several run to two printed pages in depth - there's only 2 boxes at any horizontal level - arrrows from one box to another can all be straight - their direction is straight down or angled 45 degrees

I'd like to have round corners on the boxes
I'd like it to zoom expand (if possible)

it's for a charity site, with a broad range of users so also needs to be as accessible as possible

so options are :
do it as a bunch of gifs with alt tags and tab sequencing

do as a Flash file (import from a vector draw program)

tables (where I can add round corners in the corner tds) and nest them in divs and inline style them to get them in the right place

pay for an online flowchart scheme - but would need to be low cost

they all have pros and cons!
any opinions very much appreciated
thanks