The second edition of the Oulipo Compendium was published in 2005 (first edition, 1998), but I just discovered Make Now Press, who co-published this edition with Atlas. Here's the publisher description:
Make Now Press of Los Angeles and Atlas Press of London released a revised and updated edition of the Oulipo Compendium in November 2005 in a limited edition print run of 1,000 copies to be released from Los Angeles and 1,000 copies to be released from London. The Oulipo Compendium is a dictionary of mathematical constraints used in the composition of literature. The Oulipo’s foremost concern has been to devise formal constraints and compose a few examples of each for the express purpose of pointing to the potential these formalisms create. Oulipian constraints have been responsible for some of the most original works of literature ever produced.
An editorial note about the 2nd edition: "In this second edition we have updated the factual parts (such as membership and bibliographies) without modifying the literary contents. In addition, where the English name of an Oulipian procedure is not simply a replica of the French, the French terms have been assigned their own entries, duly cross-referenced."
Buy this book direct from the publisher now. [9/2011 update: the Make Now website is down and the book is long-gone on Amazon US, though Atlas Press is still selling it.] There can't be that many copies left (before the first edition went out-of-print, I know it was being taught in a few courses, and maybe it still is). Make Now have also published two works by one of the group of people behind Atlas Press: Ian Monk.
Here is Harry Mathews on Monk's book Writings for the OuLiPo: "Ian Monk's new collection of poetry and prose is a major breakthrough in English literature. Writings for the Oulipo is powerful, witty, original, and uniquely combines dazzling verbal skills with a robust and raunchy approach to contemporary life. I've never read and enjoyed anything like it, and neither have you."
Oulipo Compendium back cover quotes:
Oulipians: rats who construct the labyrinth from which they plan to escape.—Raymond Queneau
By substituting formidably strict forms for Surrealism's controversial notion of "total liberty," the Oulipo has created an amazingly beautiful and profound body of literature, which this long-awaited volume at last brings to the attention of English-speaking readers.—John Ashbery
This one is long out-of-print too:
Oulipo Laboratory: Texts from the Bibliotheque Oulipienne
The Oulipo was founded in 1960 by a group of leading French writers and mathematicians, it still meets regularly some thirty five years later, making it one of the longest lived and productive literary groupings ever.
The Oulipo’s original aim was to inquire into the possibilities of combining literature and mathematics, but this field of study was soon expanded to include all writing using self-imposed restrictive systems. Remarkable Oulipian works have been written by Queneau, Calvino, Perec, Roubaud, Mathews (to mention only those familiar to English-speaking readers).
The group publishes a series of small booklets for circulation among its friends. This anthology reproduces six of them in English facsimile, from among the earliest (no. 3, 1976) to the most recent (at the time of publication: no. 70, 1995); it provides the English reader with a taste at least of one of the most sustained and intriguing literary investigations of recent years.