Hi, I'm a noob with a problem!

I recently purchased an M reg GS300 Mk1 Automatic, which I'm loving, all except a couple of minor issues.

I noticed a hissing sound which I thought at first was the fan but having listened a little closer its definitely on the outside. The hissing only occurs when the car is accelerating, and goes when the brakes are applied. I thought at first it may be a slow puncture, and my suspiscion was strenthened after testing the brakes at above 60mph- the front passenger wheel appeared to 'wobble'.

Since then I've checked the pressure of all the tyres- all at 28PSI, and the air pressure machine does not indicate a puncture.

Anyone have any ideas? I suppose it could be the wheel bearings which I haven't checked yet- if so that would leave the hissing sound which is starting to concern me......