Hi, I am working on L1 visa since June 2008. In w4 I declared 2 dependants but unfortunately they have not joined me till now in US. How can I file tax return based on this situation?

You can file jointly with your wife and you both CHOSE to be treated as resident aliens. This will allow you to claim the $10,900 joint standard deduction plus two $3,500 personal exemption (for yourself and your wife) plus one $3,500 for your child PLUS the $1,000 Child Tax Credit.

The downside is that you must declare ALL 2008 world-wide income, but you can at least partially offset any double taxation by claiming a Foreign Tax Credit (Form 1116).

You will need to submit Forms W-7 with your return to get ITINs for your wife and child.

Even with the downside, this is probably the best way for you to file.