I am stuck at the spot where I am disguised as the enemy and there is a blockade in the road. I went up the building everything and have no clue where to go ? 
Sounds like you're trying to contact the resistance. What you need to do is take off the disguise and just use your camo suit... Wait for the resistance member to show up, and then follow him throughout the map. You will need to keep your eye out for enemy sentries, because they'll have to be disabled for the resistance member to progress.
This is a hugely tedious and stupid mission, it may take about 15 minutes of just following this dude quietly through the streets. There are no shortcuts that I know of. On the bright side, once you finish this mission and nap over a good 10 minute intermission of mindless dialogue, there's a really cool level and a pretty decent boss up ahead.
I recently beat Resistance: Fall of Man. I got kind of bored with it, relatively fast. Haven't tried to replay it.
I also played through Metal Gear 3: Subsistence. Very awesome... controls are kid of clunky compared to MGS4, though. I would love to see the Snake Eater on bluray...
I'm looking forward to Force Unleashed and hoping to grasp the concept of LittleBigPlanet in time to pre-order for some sort of exclusive goody.