B1/B2 visa for Parents

[vicky_delhi2005]

Hi:
I need some clarifications on my parents B1/B2 visa. They already have B1/B2 visa stamped on their passports (ten year multiple entry expiring in June 2010). I have two questions:

1. When is the "latest" they can travel on this current visa (expiring on 06/2010) assuming they going to stay 6 month with me in US? Is there any minimum visa validity required to travel?

2. In order to apply for a new B1/B2 visa, when is the "earliest" they can apply looking June 2010 as expiry of current visa?

Please suggest.

Thanks.

[delhiramanathan]

1. They can enter USA even on the last day of the expiry of their visitor visa. Their stay in USA is determined what date is stampd in their I 94 forms at POE.
2.They can reapply for visitor visas after the present one expires.