The rules for the T2 Intercompany Transfer qualifying period will be changed from 6 months to 12 months on 6 April 2010. It means you will have to work for the company for 12 months abroad before they can consider bringing you over.
There were some threads earlier this week about having to leave the UK for a certain length of time before qualifying for a T2. The period is 6 months and will be extended to 12 months next April. Apparently, this will prevent people on the T5 YMS from abusing their visa.
I am not sure where business visitors fit into this rule and would need to get a reading on that particular category. But for the other categories within PBS, it's going to be 12 months.