I believe General Teir 1 visa extensions will not be affected by the recent closure of the visa from April 2011.
The following two links give some information on extensions, the leave to remain category will be processed as usual.
Check out the statement of statement of changes in immigration rules HC 698 in the following link. The entry to UK has been deleted which means the visa is no more for people applying outside of UK
http://www.ukba.homeoffice.gov.uk/sitec ... ofchanges/
The following is the link for the Immigration rules which gives requirements to be eligible for Leave to remain ( Extension).
http://www.ukba.homeoffice.gov.uk/polic ... es/part6a/
I hope the extensions are not affected. Please let me know your comments if anyone knows otherwise.
--Thanks
prash.dba