It s simple. I actually just created a thread about this. You're running Honeycomb, I assume.
Open up your browser, then tap the options menu in the top left corner. Then tap 'settings'. After that, open the 'Advanced' tab on the left and look for a option entitled 'User Agent String' near the bottom. Change this to 'Desktop', and you're done! No more mobile sites!
As to Flash Player, you can get that from the Android Market.