Download the MGS4 pack from the Plystation Store. It is free, I believe.
no not legally
There is both a Level Kit and a Costume Kit for Metal Gear Solid
There is a Metal Gear solid Level Kit and Costume kit both are $5.99
It is available and included with the Metal Gear Solid costume pack for $5.99 and as a Metal Gear Solid Snake costume for $1.99 from the Playstation Store
There is a Metal Gear Solid costume Kit and a Metal Gear Solid Level Kit at the Playstation Store for $5.99 each or the individuals costumes are $1.99
There is a remake version for the Gamecube known as Metal Gear Solid: The Twin Snakes, but that exact version of MGS is only on the Playstation.
By purchasing the metal gear solid game pack
Buy the metal gear solid add on content from playstation store and you'll get it in the levels
You either need to have a friend that already has it or you need to buy the Metal Gear Solid pack which is $5.99
It is available for download for $5.99 from the Playstation Store
abandonware
Yes. A Windows PC version of Metal Gear Solid was released in 2000, dubbed Integral as part of the rerelease that was also available for the Sony PlayStation.