Song five of seven from the Jaane Tu Ya Jaane Na soundtrack is Pappu Can't Dance, involving several vocalists: Baze, Mohammad Aslam, Tanvi, Anupama Deshpande, Benny Dayal, Tanvi, Darshana, Satish Subramanium. Like the references contained in it and how catchy the tune is!
On the word 'Pappu'
The only English equivalent I can think of is 'cutie pie'. The word is sometimes used along with gappu, as in gappu pappu (chubby pappu), when referring to a sweet male child. Some moms lovingly call their sons 'pappu', which is often used as a nickname within a household.
'Pappu' is also often used to poke fun at a person (male only). The [arguably] offensive part lies in calling a grown man pappu, which implies the weakness of a child or a lack of maturity.
A reference to Salman Khan?
No. As I said in this post, I find it surprising, because Salman can dance. Aamir Khan rubbished this as well, in this video from the music launch.
On the word 'Saala'
The literal translation of the word 'saala' is, as I am sure you must know, 'b@****d'. Of course, it is often used in a friendly context. Remember the song Roobaroo from Rang De Basani (2006)? 'Saala' also means brother-in-law, as in wife's brother, but that is not relevant here.
On the character 'Pappu'
Somewhat looking forward to learning more of this character. Sounds interesting. Is this song at a party sponsored by the alumni group at the college Jai and Aditi (characters for Imran Khan and Genelia D'Souza) attend, since we know he holds a MBA? =)
The Song (here is the trailer)
Here are the lyrics I transcribed, and alongside it my attempted translation. Here are posts related to the film, including lyrics and translations of other songs, trailers, interviews, etc.