With mobile phones present in almost every hand out there, you need to make your business visible on them as not many are using laptops and desktops to access internet. Gone are the days when a single website used to work on all platforms, now if you have website you need to have a responsive mobile website too.
Although mobile website development is a part of web development, but you need to ensure that the team holds core caliber in developing sites that work on the mobile phones.
Now that the debate whether a mobile site is required or not is over, you immediately need to start hunting for a service provider who could be a help. It is a comprehensible fact that the internet traffic is divided amongst the desktop and mobile phone users and you need to ensure that a strategy is formulated so that both these are tapped well in time.
There is no compulsion that you should start with technical apps and implementations, you can start mobile website development with a simple app and then move ahead as per the requirements.
Always go in for something hybrid and in this case responsive as then only you will have a website that works well on all platforms saving you lots and lots of money. Building a website that caters to the cell phone users is no longer a waste of money, so go for it!