I live in India which is out of the ambit for most online music stores
like Itunes, Napster or Musicmatch. I like to listen to classical
music in my mp3 player so I would like to know there if there is any
online music provider that I can use to either download or rent
titles/tracks from leading classical such as Deutsche Grammophon. I
know I can order CDs online but my intent is to be able to download
purchase/rent mp3/AAC
tracks. 

- S. Mitra

Have you tried Yahoo Music Engine?  They offer monthly subscriptions
for unlimited access to protected *.wma tracks plus the ability to
purchase individual tracks for burning to cd.

http://music.yahoo.com/

Otherwise there's allofmp3.com which sells a wide variety of music in
a wide variety of formats.  It may not, however, be legal outside of
Russia, if even there.