if its an devantech srf02,srf04 or srf08 sonar(what devantech sells), its likely that there will be an object library for the oopic already aswell as example code provided with the oopic software. From that end you are fine youve just got to decide how to connect it. it can be connected to the serial port or to an I2C port. I know definately that there is object support for the i2c connection so this is the one youre likely to want.
The srf sonars have a 5 pin connection. Theyre not supplied with header pins so there is nothing to physically connect to, you'll have to get some male headers to solder into the holes. Only 4 of these pins are needed for I2C the mode pin should be left unconnected. Without knowing what oopic board you are getting its hard to know how you would connect to it but the sonar needs the 2 I2C pins(SCL & SDA) aswell as +5v and 0v(GND). Its likely that you are going to have to make a custom connector but it shouldnt be difficult.
