In reply to Flicka: Block leading is a skill worth practicing and this enchainment is a good one to do it on due to most of the belay stances being reasonable.
The main advantage is that both climbers get a chance to rest. If you are swinging leads then the second has to climb a 40m pitch then straight away climb a 40m lead - 80m with no rest. This is fine on short days but when your doing 15+ pitches a day then the cramp can set in (i'd never had arm cramp until we swung leads on Cima Grande, not funny when your arm just locks at 90 degrees...)
Methods of doing it;
1) Cordlette: This method allows you to bring all the anchors together into one "Power Point" which you can then clip straight into. The second then comes up and clips straight into the power point when they arrive at the stance. No need to mess about with swapping ropes etc. The disadvantages of this method are that its very hard to perfectly equallise each anchor (espcially if its 3 or more anchors). It only works in one direction, if you load the power point sideways then the load will come directly onto one anchor. You can look into this really deeply and not do it or you can think that this is a method thats been used by many guides for years.
2) Use one rope set-up: When you get to the belay equalise yourself to the anchor using just one of your ropes (clove hitches etc). When the second comes, up tie them into the anchor with the other rope(their end). Quickly back coil ropes and sort out rack. The second puts you on belay and then you untie from anchor. The advantage of this method is that because the ropes are different colours the chances of you uncliping your second from the belay whilst your uncliping yourselves is vastly reduced. Also whilst your uncliping from the anchor, your second has you on a tight rope that won't become slack as you unclip your clove hitches etc. Finally,and best if you are with a novice, when you get to the next stance and are pulling ropes and putting them on belay etc, the second is on a tight rope (the one that isn't tieing them into the anchor) that will never become slack whilst the untie themselves from the belay. This reduces the 'worry factor' immensely. I have used this method for years and it works really well (i'm sure someone will point out that it has a few issues but well, there are always risks)
3) Swap ends: This is the old school method. When the second comes up to the stance, tie them into the anchor and then untie and swap ends. The ropes are then already back coiled etc. It goes with out saying that its one rope at a time and both ropes need to be tied into the anchor. This has the potential to go very badly wrong, and i wouldn't recommend it unless you are well skilled at it in advance. However many people swear by it, but they tend to be the same people who say that the best way to escape the system is to take your harness off.
Another way of speeding the day up is to move together and use ropemen/tiblocs to improve the safety.
Which ever method you use, there is no better feeling than moving fast and efficiently over steep ground in the mountains.