Discussions

So the water pressure in my kitchen and bathroom sink has gotten quite low over the past couple weeks. The bathtub/shower and downstairs bathroom are operating as usual. Would anyone have an idea why this problem would be restricted to these two taps and how would I possibly fix it?  
 
Yes I understand the easiest solution would be to call a plumber, unfortunately they don't come cheap so I'd like to attempt to troubleshoot the problem myself first if possible...

Check the screens inside the faucet on the sinks. Could be scaling from the copper lines that plugged those two up.

water pressure gauge at most hardware stores, under $20.00 screw it on to the lawn service tape and check the pressure, I believe anything 40lbs or less is kinda light. that will tell you about the house pressure.  
 
if you have an older home you could have galvanized lines servicing the upper part of the house and because of a later development copper servicing the lower level. Galvanized lines will corrode especially at joints and secondary shutoffs valves.  
 
previous poster is right check your tap filters, they will pick up sediment from the aformentioned corrosion as it flakes off.  
 
is there a difference between the pressure between the hot and cold lines on the main floor. if so then you are closer to finding the problem.  
 
if it is not the tap screens and you are totally unfamiliar with plumbing, i am sure a plumber would come in and tell you what you have and where the problem might lie. likley under $100 for a look see.