A more accurate (if longer) name for this page would be: Libraries in Munich which stock English language books. Such a title would include all libraries in town, actually, but some are better in this regard than others. Opening hours are on the libraries' own websites. All libraries are open to the public, although some will charge you a fee. You don't have to be a student to use the libraries though.
The Muenchener Stadtbibliothek has lots of English books. Via the weblink given you can find your local branch and search the book archive.
Bayerisches Staatsbibliothek (also known as the BSB, or Stabi) is on Ludwig Strasse north of Odeonsplatz.
The University Library is at U-Bahn stop Universität.
The BSB and the Uni library both participate in Interlibrary Loan (ILL, Fernleihe). The BibliotheksVerbund Bayern OPAC is a catalog of all ILL participating libraries in Bavaria. Mostly research libraries, though pre-1981 books held by the BSB aren't listed. You can also order books via it.
Also try The Bookshelf at Blumenstr 36 (Alt Katholische Kirche) at Sendlinger Tor. They have all kinds of English books at 42 euro per year for membership. Borrow up to 5 books at a time for a month. They have bestsellers, classics, children's books, history, travel guides, and a large collection of mysteries/suspense. They are open on Mon, Wed and Fri from 3 pm to 6 pm, and Saturdays from 11 am - 3 pm. The Bookshelf has books in English only! Also accepting book donations during opening hours (although not in lieu of the membership fee.) Note: The Bookshelf will be closed for its annual summer break from 21 August through 4 September. No books may be returned or checked out during this time.
Deutsches Museum Bibliothek - Their online booksearch was down so I couldn't test it, and they won't necessarily have fun books, but it's supposed to be a quiet place to study.
See also the lending library at the Twisted Bavarian.
See also the Amerikahaus Library -- primarily for teachers and students, but they do have DVDs of US TV series. According to their website they've got lots of novels too.
Amerikanistik Institut at the LMU
At most libraries you can take your laptop and plug it in there and use their electricity. Call to make sure, and when you find out feel free to add that info here.
International Youth Library -- lots of languages. Schloss Blutenburg in Pasing. Monday - Friday 14:00 - 18:00.
Lyrik Kabinett München e. V. Poetry society with library. Reopening March 2005.
The Amerikahausverein has literary evenings once a month, check the link for details. A book is decided in advance and they discuss it.
See also: English Language Books