I am on H1B and it is expiring in July 2010. I am planning to go to my home country and return back after an year with my employer's consent.
Can I do that?
------yes
Will my H1B stay valid?
---------------when you are out of US then you are not on H1 status. H1 is for US.If US employer dont revoke your H1 by writing to USCIS then your H1 petition remains valid.
Can I have problems at port of entry?
----------------if US employer has job and you have valid visa stamp then I dont see problem but at POE they may ask employer latest letter.