Well, traditionally the family of the groom is supposed to reach out to the family of the bride for a "getting to know" you thing, maybe a dinner. The grooms family has traditionally paid for the rings, the rehearsal dinner and sometimes the flowers.
That being said, it's 2014. At 26 this couple are both adults and will most likely be responsible for their own expenses. It's far more practical for you to decide what you want to contribute and, depending on the amount, ask them if they want the money or if they prefer you use it to do some of the traditional stuff (rehearsal dinner or whatever).
Someone upthread said "The mother of the bride gets to set the level of formality for the mothers' dresses, so do ask her to let you know when she's picked out her dress, or at least to let you know what type of dress you should be looking for." That isn't so. The bride and groom determine the level of formality and the mothers should dress accordingly. As MOG you should know not to wear white, and it would be appropriate to ask what color the MOB is wearing so you don't look all "matchy matchy" by mistake. But other than that, you can wear any color or style you deem appropriate. Don't let them convince you that they can dictate the color of your dress...you are not a bridesmaid so if that nonsense starts, put a stop to it immediately.
The bride & groom will do the majority of the planning, so don't be hurt if you aren't too involved in things. It's wonderful to offer to help as long as you don't push yourself on them or criticize their decisions.
As for the MOB...hopefully she'll calm down after the wedding!