Here are some links to websites with audio files for davening (ritual prayers of the services), in no particular order:

Conservative:
http://www.caa-austin.org/religious/index.php?page=shabbatserv#shabbatatcaa
http://netivottest.org/audio_guide
http://nuconservices.wordpress.com/audio/
http://www.sidduraudio.com/index.html

Conservative and/or Orthodox*
http://www.kehilathadar.org/node/21

Orthodox:
http://www.virtualcantor.com/
http://siddur.org/transliteration-support/synagogue-audio-commentary

Reform:
http://www.bethelsudbury.org/jewish_basics/text002.php3

* Kehilat Hadar positions itself between traditional Conservative and Open Orthodox. I checked the "Birchot haShahar" file and found that it neatly skips the three verses that are done differently by Conservative Jews simply saying that the nusach is the same for all verses I don't have the time to listen to enough of the other files to check for the other small differences. If someone figures out if the audio files are definitely C or O, let me know.

The Virtual Cantor website sells all the files on CD for only $20. SiddurAudio also sells CD's: the three CD Shabbat set is $46.50 and the Weekday CD is $17.50 (Odd amount: I would have thought they'd choose $18 = Chai)

The voices (both male and female) and styles vary, of course. For example, Rabbi Mark Zimmerman of SiddurAudio has a pleasant voice, but he has a tendency to add a kind of extra "uh" half-syllable to the end of words and it drives me nuts. A rabbi member of my minyan does something like this at the end of every verse when he reads Torah.

Disclaimer: I have mostly collected the links rather than really listened to them.

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Here is an online list of 33 sites with mp3 or recordings of nusach (melody of a prayer service):
http://web.mit.edu/braunst/www/nusach.html

The list has many of the sites I listed above. Some of the links don't work, but if you trim back to the homepage you can usually find the right links to the webpage with the audiofiles.

For example, the link for "Beth El Congregation - Learning our Services" is:
http://www.bethelcong.org/index.php?opti....id=42&Itemid=70

But it doesn't work, so trim the long URL back just the first part:
http://www.bethelcong.org
which takes you to the shul's homepage. Then choose the "Learning our Services" link from the left hand navigation column to get the right link:
http://www.bethelcong.org/learning-our-services

I found the list of 33 sites through Rabbi Josh Feigelson's site (I met him when he was the rabbi of the Northwestern Univ Hillel):
http://joshfeigelson.wordpress.com/torah/recorded-liturgy/
Rabbi Josh is Orthodox so he uses the standard substitutions for various references to God since he is not actually davening. For example: "Adoshem" for Adonai, "Elokeinu" for Eloheinu, etc. This can make his recordings difficult for beginners to use since he doesn't sing the words as they are actually said in actual use.

Hi, Debbie! Thank you for linking to my site, the list of 33 sites at http://web.mit.edu/braunst/www/nusach.html, or should I say, my former site. It is now no longer there, and it's moved to http://offtonic.com/nusach/nusach.html . It also has a lot more than 33 sites now and it's ever growing! Please update the link so that people can find this resource.

Oh wow, what a wonderful collection of links!

Thanks for finding this post, mauro7inf, and giving the updated info.

I was recently reminded of one of many reasons I love my lay-led minyanim: I heard two or three different tunes for many of the parts of Hallel in the several times that I heard this service over Pesach. I was once very disappointed by an Orthodox women's-only bat mitzvah done on a Rosh Hodesh in which Hallel was just mumbled through without any tunes at all.

Whoever leads services in either of my minyanim gets to choose nusach---most often standard traditional Ashkenazi with Carlebach tunes being the most popular variation. However, people generally add only a limited number really different tunes that others are not likely to know. It would make people uncomfortable if no tunes were familiar, and it would probably be considered to be in bad taste to do too many tunes that no one could follow so it turned into a "performance" rather than being participatory. To be honest, I personally have a hard time picking up a new tune. I've been at sessions in which a niggun is taught and I'm still struggling to remember it after a dozen rounds.

A favorite trick at my minyanim is also to do some part of the service using a modern tune with a similar theme to the parashah or a holiday tune. For example, for one service this past week we sang "Adon Olam" to the tune of "Dayenu" and another time to "Adir Hu". And the first part of Kedusha was sung to another seder tune, but I don't remember which.

Anyway, I'll enjoy browsing and listening to some of these new audio files.