Been there....done that.
Don't drain the oil or change the filter - just check the level and leave it alone until you get it running. Taking the old filter out will require the engine to run without any oil as it fills the empty filter housing and filter. It is better to get it started and get oil flowing immediately.
Definitely drain anything that is in the tank and get rid of it. You don't want to use any fuel that is older than the cottage cheese in your fridge!
If the fuel tank is clean inside, you may be able to leave it alone.
Wash the bike if it is dirty, take care to clean any dirt/crud away form the spark plug area, and remove the spark plug. Spray Sta-Bil Fogging Oil into the cylinder and replace the spark plug. Rotate the engine over a few revolutions if possible by removing the timing cover on the left side of the engine, and rotate it with a 17mm socket in the same direction as the wheels turn when the bike is going forward.
Remove the front (exhaust) valve inspection cap and spray some form of oil into the head to lubricate the cam and rockers. Don't use WD40 or any light oil - use something with some thickness to it. (The Fogging oil is better than nothing). There is a small rectangular well under the cam that retains oil and lubes the cam at the startup - if you can get some motor oil in there it is the best protection for the cam/rockers....use a squeeze bottle with a 6" length of tubing.
If your fuel tank was clean you may try the petcock to see if fuel flows. Put fresh fuel in the tank, turn the petcock to PRI, and open the drain screw on the bottom of the float bowl and see if anything flows out. If it does and it looks clean - close the petcock.
You obviously are going to need a new battery.
Then.....see if it will run!
If it starts and runs.....you can change the oil and filter after it is running a few minutes.
The test ride will let you know if you need to clean the carb.
Good luck!
Here is the link to the bike I brought out of storage.
http://suzukisavage.com/cgi-bin/YaBB.pl?num=1440293732