I submitted my tier 2 general application from within the UK through the standard postal application route. I will need to get my BRP done also. I think it should be a straight forward application. I am currently on a work permit and working for the same employer. so in essence it is just an extension.
You don't get your BRP 'done' as such, because your BRP is your Tier 2 visa... you will be mailed your BRP when your visa has been issued.
What you will need to get done is your biometrics though - UKBA will sent you a letter in the post within a few weeks of receiving your application, inviting you to make a biometrics appointment at a post office. Once you have done this, they will process your application.
Anyone have any idea how long the processing time is? Can we book tickets for a holiday over Easter?
I'm not sure on current processing times as we haven't had many people here on UK-Y applying for Tier 2 from inside the UK recently, but I would estimate 1-2 months for processing AFTER you have given your biometrics.
I would wait until you have received your passport and BRP before you book any holidays though, because there's no guarantee you will get it before Easter (you might, or you might not).