Buses run directly to Leh from either Manali or Srinagar. Enroute to Leh one can stop in a number of places , most will get off in Keylong , the administrative center for Lahaul. Overlooking Keylong is the Kardang monastery. This is the choice that most travelers will want to take due to the tense security situaton in Kashmir, however the road is only open from June to mid October due to snow fall. There are shared taxis from Manali which start early in the morning and reach Leh early next morning.Tourist buses from HPTDC and the local HRTC buses, stop overnight in Keylong.There are also minibuses and shared cabs that makes a overnight stop in Sarchu - this comes with a high incidence of altitude sickness , since Sarchu also dubbed "The Vomit Hilton" lies more than seven hundred meters higher than Leh , at 4253 meters. Coming from Srinagar there are a few interesting places to stop en route : Kargil at 2693 meters where the buses stops , the best choice for altitude acclimatization , Lamayuru and Alchi that also offer accommodation. The opening and final closing of both roads, but no major events in between, are announced on the the official Leh website. Srinagar-Leh news updates are found here, Manali-Leh here
Daily flights to Leh are run by Indian, Jet Airways and Kingfisher Red from Delhi, Srinagar, Jammu and elsewhere. These are, however, subject to inclement weather and may be cancelled at any time, keep your schedule flexible. Altitude sickness is also a worry given the altitude.
You can ride in to Leh between June and Mid october when the roads are open on a motorcyle too.
Bikers usually follow either of the 2 routes
1. Delhi -> Chandigarh -> Patni Top -> Srinagar -> Kargil -> Leh
2. Delhi -> Chandigarh -> Manali -> Sarchu -> Pang -> Leh