Q: iPhone and iPod on same music library

Hey Behr0208,

It's no problem syncing multiple devices to one computer / iTunes library.  iTunes keeps track of each device and syncs to them separately.  Make sure you unmount the connected device before you unplug it. :-)

For an overview, please see 

Sync your iPhone, iPad, and iPod touch with iTunes - Apple Support

For different syncing scenarios see

How to use multiple iPhone, iPad, or iPod devices with one computer - Apple Support

It sounds like you want the section:

Sync devices to playlists

You may use multiple devices on a computer without creating multiple user accounts. To do this, you can set iTunes to update each device with only certain playlists. This method allows you to put all your music on, for example, your iPod and keep your iPod shuffle updated with only your workout music. Here's how to do this with iTunes:

1. Create new iTunes playlists on Mac and Windows that contain all the music you want to sync to each device.
2. Sync your device.

Note: iTunes for Windows does not support syncing multiple iPod devices at the same time.

Enjoy.

Great. Thanks for letting us know, Behr0208.