Nothing will change come the launch of CW. You will just notice that well watching WNLO SD on its two frequencies, the graphics won't be UPN anymore.

supposely, WIVB has getting an HD encoder for the CW network a 'priority' and in best case scenario, will have WNLO is HD in 2 to 3 weeks.

my guess is that it will be towards the end of this year, start of next year before we see Smallville, Supernatural, Everybody Loves Chris, Veronica Mars (or actually SUNTV may be showing that in HD this year) ...etc in HD.