You can also simply select the portion in timeline and export it to wav, then convert to MP3, or if you have the MP3 encoder of SONAR, export directly to MP3. The former way is more recommendable than the latter, IMO.
One fluent way to separate the songs of a long recording is also:
Select a song and drag it to a new track, name the track accordingly.
Do this to every song and then you can export them to separate wavs in one go.
Unfortunately you'll need to rename the tracks after export.
Hmmm..one thing: Is it a multitrack recording or a stero track? That last suggestion of mine is only for a stereo track.