What is the difference between osmotic potential and osmotic pressure?
Osmotic pressure: pressure applied by a solution to prevent the inward flow of water across a semi-permeable membrane. 

Osmotic potential: the potential of water molecules to move from a hypotonic solution to a hypertonic solution across a semi-permeable membrane. 

Osmotic pressure can be calculated using the following formula:

$$Π = iMRT$$

where
$Π$ is the osmotic pressure in atm

$i$ = van 't Hoff factor of the solute.

$M$ = molar concentration in mol/L

$R$ = universal gas constant = 0.08206 L·atm/mol·K

$T$ = absolute temperature in K

The following page has a worked out example. 

As for your question on solute potential vs osmotic potential, the answer is that they are indeed the same. You can compare the formula for $\Psi_{\pi}$ on the wikipedia page and the page of this pearson textbook. These formulas are the same:

$\Psi_{\pi} = -Π =-iMRT$  

So there's a simple relationship between osmotic pressure and osmotic potential.