I use
AudioGrabberEdit to add: after you install it, you'll have to download various codecs as AudioGrabber doesn't come with one to convert the songs to MP3 (some are free, some aren't).
Internal encoders
Audiograbber does not come with any MP3 encoder of its own but it can use some other encoders. It is recommended that you download and install LAME's freeware MP3 encoder dll and use that one with Audiograbber. LAME is fast and gives very good sounding MP3 files.
Download LAME's MP3 dll from http://www.audiograbber.com-us.net/download.html or http://mitiok.cjb.net. Unzip the lame_enc.dll to the same directory as audiograbber.exe and you will have an internal MP3 encoder that goes all the way up to 320 Kbit/s in Audiograbber.
LAME's official homepage is at http://www.mp3dev.org
Another good encoder that works good with Audiograbber is BladeEnc. This encoder is also freeware so it won't cost you a dime. It is far from as fast as Xing's encoder but many people thinks this encoder produces better sound quality.
http://bladeenc.mp3.no
Other encoders that are supported internally by Audiograbber are Fraunhofers MP3 acm codecs and Qdesigns MP2 acm codec. Audiograbber is distributed with LibVorbis.dll so it can make OGG files for you. Microsofts Windows Media Audio V2 is also supported (which gets installed if you install Winamp). Finally and last SONY's ATRAC3 acm codec is supported and you can get that one from http://www.minidisc.org/atrac3.zip. Info on ATRAC3 can be found at http://www.minidisc.org.
External encoders
Xing technology has made a very fast MP3 encoder that works good as external codec in Audiograbber. You must have their registered version and use x3enc.exe as external encoder (x3enc.exe does currently not come with their trial version). It cost however only $19.95 to register (27 September 2000).
http://www.xingtech.com/products/mp3encoder/
GOGO MP3 encoder (freeware): This one is based on LAME's sourcecode and it has been optimized for speed. Homepage http://homepage1.nifty.com/herumi/gogo_e.html Download: http://homepage1.nifty.com/herumi/soft/gogo2/gogo235-win-con.zip
MP3Enc: Fraunhofers new standalone encoder, slow and expensive ($199!) but with good sound quality. http://www.opticom.de
. Download a demo version from http://www.sonicspot.com/mp3enc/mp3encdemo_3_1_win32.zip
Fraunhofers L3enc was previously used to create MP3's. It can no longer be downloaded from http://www.iis.fhg.de/audio but I keep the link here for nostalgic reasons.
Monkey's Audio (freeware). This is another interesting format that differs from the others in the way that it is lossless compression. Lossless means that a file can be encoded and decoded back without losing quality, just like the .zip format. MP3 is lossy compression which means that some data is lost during encoding and it can never be fully restored. Lossless will of course not compress as much as lossy but Monkey's Audio compress the file by around 50%. And with Monkey's Audio you will not have to worry/listen for artifacts in the song. There are simply no artifacts since what you hear is identical to the original wav file. You can encode and decode as much as you want without losing quality! http://www.monkeysaudio.com. (Set to Mac.exe as external encoder in Audiograbber).
FAAC (freeware). This encoder makes AAC (Advanced Audio Compression) files. http://faac.sourceforge.net.
MPG+. http://www.stud.uni-hannover.de/user/73884/audiocoder_eng.html.
There has also been a general Encoder plugin released by Alexander von Gostomski. With his plugin you can use both AAC, VQF and a Real Audio encoder! The homepage has unfortunately vanished but the plugin can still be found here:
http://www.audiogalaxy.com/software/plugins/windows/jaep_plugins.zip
You can also check out http://www.audiograbber.com-us.net and see if there are any new encoders available.