Depends where you're flying from and who with but Marco Polo is the nearest by far and the more modern.

I've only ever done MP to Venice proper but there is a direct route to Lido from the airport via waterbus.

Clicky click on this: Map of routes

Also click on the Union Jack for translation.

how much would I be looking at ?
or is there a bus shuttle service ?

any recommendations much appreciated

There is a regular bus shuttle to Jesolo. Have a look at the ATVO timetable page:

http://www.atvo.it/orari/pdf/MarcoPolo.pdf

The atvo.it page is useful for all sorts of transport around Venice, giving routes, times and prices.

Another useful page for Jesolo is:

http://www.jesololido.com

Have fun.