hi... I'm new to this board but have been riding for a year now... you will love clipless pedals! Excellent idea to practice on the trainer... then once you're on the road, just unclip early for the first ride until you get used to the whole stopping and unclipping thing...

as to your seat... have you had your bike fit professionally by a reputable bike shop? If not, start there... if so, hopefully the new seat will help... I had a lot of problems in the beginning with pain during and after rides and then not being able to pee 'cause it hurt! I finally went to a different place than I bought the bike and got fitted by a woman who was really good...my seat was too high and too far back... which meant I was leaning reallly far forward for the entire ride... made some adjustments, bought a Terry Butterfly (I'll never ride any other saddle now) and wha..la!

A good way to tell if the seat is too high is to have a friend ride behind you... if you rock back and forth on the seat, your hips don't stay level, then the seat height is wrong...

Forgive me if you already knwo this stuff... I just know it made a world of difference for me... I look forward to riding now!