Can somebody name this instrument for me?
 
At the 15-second mark: There is a guitar that chimes in over the bass. In the next section, it multiplies into a chorus. The instrument that goes: "Bew...bewbewbewbew bew bewbew..."
https://www.youtube.com/watch?v=Hn-enjcgV1o
 
Can someone tell me what this instrument is? I would like to use this in my song. (I have all Cakewalk SoundCenter packs, Studio Instruments, Roland GrooveSynth and of course, TTS.)

This is a guitar going through a Leslie Rotary Speaker ... it was a fad in those days.  Hope this helps.

I've always thought of Player as being a tight band but that may be the worst lip syncing I've ever seen (unless the drummer has a ride cymbal that sounds exactly like a closed HH ...and crashes that don't move when you hit them).
BTW, it sounds more like "Dew...dewdewdewdew dew dewdew..." to me 

SONARtist
This is a guitar going through a Leslie Rotary Speaker ... it was a fad in those days.  Hope this helps.

^^^ This
From 0:13 - 0:24 it's a single guitar line
From 0:25 - 0:36 it's a harmonized guitar line 
 
of course, there is reverb and maybe a little delay added as well.

Unfortunately, a Leslie sim isn't included in any of SONAR's bundled effects or instruments, AFAIK. However, there are many third-party options, including a few freebies. Many effect collections such as Guitar Rig and Amplitube include one. Xils makes a good one, so does Meldaproduction.
 
Google "VST Leslie". 

Are you sure it is a Leslie Rotary speaker?
 
I have never played through a real Leslie Rotary speaker (so what do I know) but the oscillation rate on that sound in the video seems pretty fast. Can a Leslie Rotary speaker rotate that fast?
 
Plus, there seems to be almost a "wah" type of affect. Could it be a phaser? I have played phasers that kind of sound like that.
 
Either way, it sounds pretty cool. I had forgot about that song. I think the last time I heard it was on the Simpsons when Homer lost Maggie when he was baby sitting her :-)

Flanger.

Could be any one of a number of effects. I doubt it's a physical rotating speaker, though, it's something electronic. If I get a chance tonight I'll see if I can come up with something. It would be a fun puzzle.

An interesting article about Leslie cabinets mentioning "Baby Come Back" as an example of playing guitar through a Leslie http://www.theatreorgans.com/hammond/faq/mystery/mystery.html 

scook
An interesting article about Leslie cabinets mentioning "Baby Come Back" as an example of playing guitar through a Leslie http://www.theatreorgans.com/hammond/faq/mystery/mystery.html 

Oh. Well there you go. :-)