Technically there is no Correlation between the H1b and GC Process..You can File GC Right away as long as Meet the requirements in Employment based Criteria(EB1,EB2 or EB3)..You don't have to Wait till december to File for GC(That's when your H1b Kicks off).It's always better to file GC at earilest and as long as you can maintain valid status during the GC Process..

It really depends upon which Employment Category u r Filing GC..And let me Reiterate this once again "Simply having Master's degree in a particluar field doesn't mean that u can File GC on EB2. ..It's the nature of the Job that determines whether u are eligible for Eb2"

The Biggest Problem these days is the Labor processing(PERM)..Couple of Days back i found that DOL is processing the Labor for People that have Filed in Nov 2008.Appears as if there is Backlog in Labor..

On the Best case it will take a week to Approve the Labor and on Worst case it will take 8-11 Months to Clear it..I-140 for EB2 normally takes 2-4 Months to get Approved and I-485 takes again 1-4 months to Get cleared....Check to see if you can File Premium Processing for I-140..Will clear in 1 month if there is no RFE..

On the best case i have seen PPL getting GC in 4- 6 months after Filing labor..On the Worst case it won't take More than a year and half if there are NO RFE's in the Case....

Give and Take I agree withe Danphe's Timeline..

It's always Better to File GC on EB2 as the PD is Current for Nepal..

Hope it Helps..