How do you install those little turn signals that can go on the side fender of a 240 in place of the volvo emblem. and where is the wiring to connect them to.

Don't thank me, thank Dave Shannon:
http://www.homestead.com/volvo2/sidelights.html

Erling.
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My 240 Page

I recently did Euro fender signals on my 940, but it has pre-shaped holes behind plastic badges on the fenders. The 240 would need holes drilled in the fenders with a lot of filing to make the rectangular hole accept available lights.
My reasoning for this was for safety in lane changing, not a 'cool' factor. If all you want is a flashing light on the side of the car, I would recommend putting some generic lights on the bottom side of the outside mirrors. That is what I plan to do on my 240. But only after I replace cam seals, rear bushings, recharge AC, etc.
If you look into the archives, there is much info on fender signals. Fishing the wiring from the fender to the front corner turn signals is an exercise in patience. The actual hookup is very simple.
Mark
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'94 940 Wagon, '84 240 turbo sedan

Nope - not true. My '91 and '92 240's both sport properly-shaped holes to accept the same fender signal lamps. Use monofilament or dental floss to get behind the Volvo badge and expose the holes.

On the 240, you gots to roll your own. Pretty simple, though - just splice into the front parking light/turn signal leads. Took me maybe 2 hours on my 240's, lots longer on an 850.