Is it possible to use magnets to launch small light weight satellites into a orbit around the earth to provide a net like coverage around the earth? Is it practical and will it be useful?
Theoreticaly? Yes. There are papers about doing this either with a Coilgun or a train-like launch system (the (magnetic floating) "train" would accelerate along a miles-long track which at the end bends upwards).
But there are three very difficult problems to solve which make it rather unpractical:
Speed vs. drag: To reach a stable orbit you need a start-velocity of Orbitspeed (~8000 m/s) + Loss to gravity drag + loss to drag. The last one is the game-breaker: at ~15 km/s the air at the first few kilometres of atmosphere will be thick like a wall and will:
a) kill most of your velocity really fast and
b) create a lot of heat due to shock-heating.
Magnetic shielding: Your payload will be exposed to very strong magnetic fields while in your acceleration system. You either need a very robust satelite (like a simple brick of steel) or need to shield it somehow.
Accelaration: Since you need a huge starting-velocity, you need either really long tracks/barrels (like 100 miles long) or you need to accelerate at several 100s of Gs … Not a problem for a brick of steel, but your satellite will most likely be rather fragile.