I started out with both helis and airplanes at about the same time just 2 years ago.  I feel that I am a decent plane RC pilot, but my heli skills are still very much lacking.  And I say that because...

For me (and a lot of others as I have read) helis are a lot harder to fly than an airplane.

Also, my nervousness when flying a heli was a lot more intense.  Not just for any one reason...but a multitude.  IE...my helis are more expensive to crash.  You constantly have to "fly the tail" on a heli vs. an airplane tail always follows its "nose" on its own.  A lot of time is invested in building a heli AND setting it up correctly (I have more time in setup than building).

To answer your question, as also to agree with MinnFlyer...I think that helicopter skills will definitely help your plane flying.  I notice this more on models like say my gas cub.  I find that if I dont coordinate my turns on the cub (flying the tail so to speak)...that the turns look quite awkward and almost un-natural.  Add in some slight rudder with aileron and the cub turns as nicely as an aerobatic plane...say my Yak54 or such.

When learning lots of people will say not to focus on the rudder.  I feel though (and Im no expert) that learning rudder as soon as possible will only help you.  There will be times when you have to land in a cross wind and if you dont know how to use rudder...you may not be able to land without crashing.

So learn the rudder as quickly as you can become comfortable with it.  And learning on a heli will help this tremedously.

Also...if your heli is a co-axial one.  It wont transition over to a FP or CP heli much other than throttle.  Co-axial helis are fun...but really dont teach you much and probably can create "bad habits" on more sophisticated helis.  Best starter heli to get the real feeling of flying a helicopter, IMO would be the Blade mSR.

Goodluck!