Urgent: visitors visa for parents

[quest]

Hi,

my current H1 will be expired on Augest 2007. Now if I want to sponsor visitors visa for my parents, can I do it anytime or I shall have to wait for my fresh extended I-797.
Please let me know at your earliest.

[Raj_Raj]

Even though its not mandatory, its always better to wait for the 797 - just in case.