What are the actual suttas in which the Buddha described how to meditate? A list of all such suttas would be greatly appreciated.
To straighten view before meditation: Samma,ditthi Sutta
My favorite sutta on meditation is Cula-suññata Sutta (The Lesser Discourse on Emptiness). Thanissaro Bhikkhu provides a good commentary on this in his article The Integrity of Emptiness, the section called "Emptiness as an Approach to Meditation".
The two other suttas everyone else mentions - Anapanasati and Satipatthana suttas - are very good too.
There are also nice tidbits in the Northern recording of the Anapanasati Sutta, called Ānāpānasmṛti Sutra from Ekottarika Āgama.
Also, if you are specifically into Jhana meditation, then Samadhanga Sutta provides the canonical definitions of the Four Jhanas.
Gelanna Sutta is the sutta through which Buddha provides instructions on how to meditate. Other forms of meditations are Anapanasati sutta,Satipatthana sutta, Bhikkhunuppasaya Sutta.
In Buddhism, the Tripitaka (in Pali) is earliest collection of Buddhist teachings and the only text recognized as canonical by Theravada Buddhists. Tripitaka means 'three baskets' from the way in which it was originally recorded: text was written on long, narrow leaves, which were sewn at edges and grouped into bunches and stored in baskets.