There are a total of 10 Glyphs hidden throughout Rome in Assassins Creed: Brotherhood. Each of the Glyphs is broken out by the areas and then specific buildings or smaller areas they are located within.
Once you find the Glyphs they'll have to be climbed into and then that's where the real fun begins. There's some visual help for those puzzles below the Glyphs locations guide.
Campagna District Glyph Locations
1. Caserma di Alviano - Find the buyable faction building and locate the large arched gate structure near it. Climb on top of this structure and run east towards the first corner. When there, activate Eagle Vision and you'll notice an opening on the outside of the wall. Drop down to it while holding B or Circle and you'll grab the ledge. Flip up inside and the Cluster is found.
2. Castra Praetoria - This Cluster can be had later in the campaign inside the walls of Castra Praetoria. Head towards the inner East end and spot a little outhouse looking building with a door that takes up most of its facade. Climb on top, hit Eagle Vision and the Cluster will be seen.
Centro District Glyph Locations
3. La Rosa in Fiore - Locate the Courtesans' headquarters and climb up towards La Rosa's roof. The Cluster is up near the top and can actually be seen from street level when you activate Eagle Vision.
4. Palazzo Senatorio - You'll find this Cluster on the back of the Palazzo Senatorio building. Climb across its back side until you see a red banner hanging, about halfway across. Activate Eagle Vision and the Cluster is just to the right of the banner.
5. The Pantheon - One of the most obvious buildings in Rome houses an easy Cluster to find. Enter the dome building, activate Eagle Vision, turn around and look back up above where you came in and the Cluster location is right there. You'll need to "drop" into the Cluster from the roof ledge above while holding B or Circle.
6. Santa Maria dei Miracoli - Look for the tall tower just west of Santa Maria dei Miracoli. The Cluster is on the tower's north face, just above the roof line. It's easy to spot after activating Eagle Vision.
Antico District Glyph Locations
7. Acquedotto Claudia - For this one travel to the north side of the acqueduct. Look up with Eagle Vision and you'll spot the Cluster. A direct approach won't work to reach it, so head up the tower on the opposite side and make your way across the acqueduct's top to it.
8. Aventino - Look for the tall assassin tower that sits up on top of a hill. The Cluster is about halfway up this tower on the north side.
9. Il Colosseo - This is the Colosseum Cluster and is located on the very edge of the northwestern end. Get up on the top lip with Eagle Vision on and you'll see the Cluster below. Make your way down to it and eventually drop into it using the B or Circle button trick.
Vaticano District Glyph Locations
10. Castel Sant'Angelo - The last Cluster is up in the Pope's castle, just below and to the right of a big rose window beyond the inner wall. Walk the inner wall with Eagle Vision on looking towards the castle and it's easily spotted.
Locating all the Glyphs in Assassin's Creed: Brotherhood is the easy part. Once you get inside there are a series of aggravating puzzles that need to be solved in order to reap the Truth Clusters rewards. These videos from YouTube provide a walkthrough guide of the Glyphs locations as well as solving the Truth Clusters puzzles within them.