To wire two 16 ohm speakers to provide 8ohm mono/16ohm stereo operation, you will need:
2 x 16ohm speakers
2 x 1/4 barrel connectors (one of them has to have 'break' contacts, like:
http://www.maplin.co.uk/module.aspx?ModuleNo=1298&doy=10m1)
wire.
For the left (the connector to be used for mono operation), connect the + and - points on the speaker to the non-break contacts of one of the jacks, and the same wires to the break contacts on the other jack. The non-break contacts on the 2nd jack go the + and - on the right speaker.
When you plug in to the left connector, the signal goes to the left speaker, and because there is nothing plugged into the right socket, it also goes to the right speaker (because there is nothing to break the contacts apart). But when you plug into the right, it will disconnect so they both operate on their own (just remember to switch the output impedance on your amp). This is how i've got my 2x12 wired, so i know it works :P
Hope that helps, if you want a diagram, i can try and draw one up for you :)