Marksmanship question

If at all, does having a higher marksmanship increase your regular attack damage? If so, how much? Thanks in advance.

Yes and heres more info on it

http://www.guildwarsguru.com/content...nics-id674.php

Very much so. Most of your ranger bows have a attribute link to your marksmanship. Without points in marksmanship, the damage of your skills is also minimal. How much it increases depends entirely on what skill you are using at the time... most skills increase at different increments in relation to your attribute level.
Do some searching through the database on this site..more pointedly into the ranger skills. Under the skills themselves.. where you see something like this..

Powershot - does+13-25 damage. (as example)

The +13-25 damage is the add on from having points in your marksmanship.
13 if you have nothing...25 if you have a full level 12 attribute.

That should give you idea what you are looking at on the skill listings.

Higher marksmanship will only increase your normal attack damage on a bow linked to marksmanship. I've heard rumors of bows linked to expertise (I hope its true) and with those you can still do good damage while bypassing marksmanship altogether.

which basically says that you will only do 100% of your normal attack damage when you have a level of 12 in the appropriate attribute line for that weapon, (excluding staves and wands).

Unless you love doing math calculations:
http://paladins.viperhosting.net/?p=stuff&s=attrdmg