The mountain dominates the horizon to the northeast when seen from Mera Peak.
Chamlang is not a popular peak by any means. I found a few climbing reports (see "External Links") on the Internet but information is far and few in between.
Japanese Academic Alpine Club of Hokkaido via the south ridge. First ascent
1986 Second ascent via the west ridge. Japanese expedition
1987 Korean-Nepalese expedition via the south ridge
1990 West face via the west ridge. German expedition
1991 First British ascent via the south ridge
1981 Reinhold Messner and Doug Scott climbed a minor summit (7010m) via the north face (*)
1984 Doug Scott and his party made a east to central summits traversal1989
East summit via the north face. Dutch women expedition
As far as I know the north face remains unclimbed as of Dec 2015.
These are all I can find. PM me if you know any other.
Virtually all climbers start the walk-in from Lukla. To get to Lukla, you can catch a mountain flight from Kathmandu. Flight cancellation is pretty common so it's wise to schedule some buffer days (both ways).
From Lukla to the Chamlang Base Camp, follow the route to Mera Peak
up to the Mera La. There are two routes:
Lukla (2860m) - Puiya (2796m) - Pangum (2846m) - Narjing Dingma (2700m) - Chalem Kharka (3440m) - Khola Kharka (4120m) - Kote (3500m) - Tangnag (4140m, 2 nights) - Khare (4940m, 2-3 nights) - Mera La - BC
Lukla - Chutanga (3400m, 2 nights) - Tuli Kharka (4400m) - Kote - Tangnag (2 nights) - Khare (2-3 nights) - Mera La - BC
The first option is longer but allows more gradual acclimisation while the second option involves a very steep ascent of the Zatra La (4600m) on the 3rd day.
You'll need a climbing permit for the peak and trekking permit for the walk-in.
Climbing royalty for foreigners: $500 for spring, $250 for fall and $125 for winter/summer.
When to Climb
Spring (March-May) or Fall (Sept-Nov)
There are many tea houses along the way from Lukla to Khare. However most big groups (mostly to Mera Peak) choose to sleep in tents and use facilities provided by the tea houses.
I also heard (from a lodge owner in Khare) there are now two simple lodges in the Hongu Valley but I can't verify that myself.