Today was looking over the statistics on Latitude history and I noticed that it registered another place as my home, it is actually one block away from the adress it says.
Is there a way to change or set my home's location manually?
You can manually set the location using an iGoogle gadget or through Firefox. What you are probably seeing when the location is "one block away" is that GPS is not actually turned on on the handset. The phone is probably using positioning that is determined used cell phone tower location, so it will get you in roughly the correct place, but not the exact location you would expect if GPS was turned on.
If you go into Maps on your phone, press Menu, press Latitude, press yourself, press "View your location history", then press Menu you should see an option to change your Home and Office/School locations.
Turn Wifi on if you haven't got it on already. You don't need to actually connect to it, just to have it enabled. Google uses the known locations of wifi points to help its GPS calculation (don't know if anyone else does, mind you)
If your internet is from a VPN or a server it shows the location of these servers instead of yours using the same method as the new Geolocation function in HTML5 i suppose