Switching from Post study work PSW to Tier 2 Dependant

Hello Gurus,
Please I need urgent help on the following.
I have been on UK student visas for 9 years, My PSW visa expires soon.
My wife is on a 3 yrs Work Permit Tier 2 and I want to apply as her DEPENDANT (TIER 2 DEPENDANT)

1)Can I do so whilst in the UK? or do I travel abroad?
2) What form do I require?
3) any UKBA links you provide will help.
4) Any advice on 10 year long Residency?

Many Thanks in advance.

1. You need to go back to your home country to apply for entry clearance.
2. You can download the form from UKBA website for your country of residence.
3. http://www.ukba.homeoffice.gov.uk/visas-immigration/
4. If you leave UK while you have a valid visa and you return to UK with a fresh entry clearance within the 6 month period, you should be fine.

IMO