Before you can fix, you have to determine what needs to be fixed, before we can determine "homefixes" we would need to know your technical ability and the available resources - personally I can deal with anything short of the steering box itself in my driveway, I have no idea what you can do. I will need to take it out for alignment after, but I can get it close enough that it can be safely driven to the alignment shop.
A Sidekick has three "links", each with two "ends", looseness in any one of these shows up as play in the steering wheel, and if they are all loose, then the individual "loosenesses" are seen as accumulated play at the steering wheel - there's an idler arm on the passenger side, the steering box on the driver's side, universal joints in the steering column, all of these can contribute, as can worn/loose ball joints & bushes in the front suspension and worn/loose wheel bearings.
Some one will need to go through every item I mentioned above and inspect them to determine if they are serviceable or a contributor to the looseness, this inspection can be as simple as jacking the wheel off the ground and shaking it whilst observing the linkages to see where the movement occurs, or it may involves disassembly.
I don't recommend adjustment of the steering box unless you know what you're doing and why you're doing it - the steering box, if it is worn, will have the most wear in or around the straight ahead position and if it's adjusted to remove the play, there is the possibility of it binding at other, less worn points in it's travel.
