VoIP Provider Help

We've just taken on new premises and have taken a "Advanced" BT line and broadband.

We're not so worried about outbound calls as most will be made from mobiles on the road.

We'd like an easy to remember phone number for customers to call in.

We'd most of the time like to be able to divert the VoIP to our mobile(s) and occasionally to another land line. ** This is the most important bit for us.

Based on the above requirements, can anyone suggest a good company to use and is what we feasable? Type VoIP into google and it's Reseller CITY! I'd prefer to deal direct with a reputable company.

Thanks, Paul.