Start from the Longs Peak Ranger Station and hike to Mill's Glacier at the base of the Diamond (go past Chasm lake).
Normally Lamb's Slide is a moderate snow climb at roughly 45 degrees, though it gets icy in late Fall. I climbed it in late July, summer of 2002, during the unusual drought, and it was extremely icy. Climbed perhaps 150 m with crampons and single mountaineering axe (crampons were not essential), the could no longer avoid the pure ice. Tried ice climbing 10 m before giving up and scrambling along the rock on the left side, which was easier than expected (3rd class). The entire route could be climbed along this rock side, or, with appropriate gear (depends on how icy it is) one could climb the entire way on snow/ice.
There are several options on how to finish the route. One can climb Lamb's Slide to Broadway level and then do Kiener's (a very respected route) or continue all the way to the Loft (never harder than 3rd class, but loose rocks in places). From the Loft, it is an easy 15 to 20 minutes to the top of Meeker, or a little over an hour to the top of Longs via Clark's Arrow Traverse (follow the cairns and expect to have to downclimb a tricky chimney before starting the ascent). Lamb's Slide also serves as an approach to Zumie's Thumb and other climbs in the area (just as Clark's Arrow is a good approach to the Palisades).
In addition to standard gear, I recommend the following:
Early summer when Lamb's Slide is all snow:
Mountaineering axe and sturdy boots very useful, though perhaps not mandatory if you are extremely skilled (or if you want to avoid the snow and scramble on the side).
Late summer and early fall (or mid-summer during drought years):
Same as early summer, but expect ice in many sections
Mid to late fall:
Unavoidable ice. Crampons mandatory. Possible perhaps with one mountaineering axe, but two ice climbing axes recomended (and rope and ice gear, depending on skill/courage)
I have no experience. Use common sense and look at a guidebook.
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