Lilly, the manufacturer of the impotence drug Cialis, the biggest competitor of Pfizer's Viagra, are making a determined attempt to become the top product in many of the markets where Viagra has been king.  They have expanded their product offering to include a one-a-day pill which they describe as "Cialis for daily use, so you can be ready anytime the moment is right."  This is backed up by their clever TV campaign which doesn't mention their product by name but directs interested viewers to their 40over40.com web site, where they can answer their own questions about impotence and what type of product would be right for them.  The interested male is then encouraged to visit their doctor and tell them what type of impotence product they think will suit their lifestyle best.  The hope is that this will boost Cialis sales.  All this effort is directed at the most affluent markets, as these are the markets that Viagra has been so successful in.  These are the markets where Cialis wants to make sales.  There is anecdotal evidence that they are gradually making a substantial dent in Pfizer's sales.  Cialis Sales are growing.  However like many other things in life one size does not always fit all and Viagra users often return to the product they used first.  Lilly will find this a long battle but the rewards are worth the effort.