3d box 'pitch' question? (SOLVED)

Can anybody help me with the following-

My game has the following objects

A 3d Box object (gun) with 2 buttons(up and down) that change the boxes pitch.

A cross-hair sight that only moves in the Y direction (depending on the 3d boxes pitch)

The 3d boxes pitch range needs start at 24 degrees and end at -24 degrees.

When the 3d boxes pitch is at 24 the cross-hair's Y position should be 240.

When the 3d boxes pitch is at -24 the cross-hair's Y position should be 440.

<img src="http://dl.dropbox.com/u/22173473/question.png">

Thanks in advance.

440 or 480?

crosshair.y=lerp(440,240,(3dbox.pitch+24)/48)

440 or 480?

crosshair.y=lerp(440,240,(3dbox.pitch+24)/48)

(The Y is 440)

Thanks for responding, my next question is how do i implement this?

For example i have the following event(s)

+ down: Button clicked

-> barrel: Set pitch to barrel.Pitch-1 degrees.

What condition/ event combination would i use to set the 'crosshair's Y position?

Thanks Lucid, i downloaded your 'quicklerptut' example and worked it out from that.

Brilliant!