I've used this spray as recently as last Sunday. It is a bottle that screws onto the hose. When you turn the spray bottle on, it draws the product up into the water spray and it applies it evenly to the lawn. I used it the day before an outside party and no one complained of any bites...and trust me, Washington, DC has some nasty mosquitos like the Asian Tiger mosquito. To give you an idea of how bad they get without control, I went out last Saturday to get a few veggies from the garden. I was out there 5 minutes tops..I had 15 bites and swatted another 10 or so mosquitos that hadn't bitten me yet.
The cutter spray does work, and it works well. I am leery of spraying it on vegetables or herbs, although the label says it's okay, but I have no problem spraying it on the lawn.
I found it at Home Depot, although pretty much any mega store should carry it. I saw it in a Wal-Mart in NJ over the 4th weekend, so I know it is available all over the east coast, at least.
I don't know if it really lasts up to 4 weeks, as it says, but it does at least work for 2 weeks.
Just make sure you cut the lawn to about 3 inches, then spray.