If you want one that is ready to play, you can buy one here: http://www.etsy.com/listing/43908950/crazy-looper
These instructions will give you all the info you need to build a crazy looper, Schematic, software file etc. I got the circuit board made but you can easily use vero board because it's such a simple circuit.
1 x 100nF Capacitor (C5)
1x 10nF Capacitor (C6)
2x 10k Pot(spline shaft) (VR1 VR2)
2x 10K Resistor (1/4W) (R2 R4)
4x 1K Resistor (1/4W) (R6 R7 R8 R10)
1x Regulator 78L05 (5V) (IC3)
1x Ic Holder 8Pin
1x Picaxe 08M (IC2)
1x 3.5mm Socket(stereo switched) (SPKR)
2x LED (RED) (LED1 LED2)
2x Knob (Grey)
1x Battery Holder(9v)
1x Circuit board
1x LDR(10M) (SW1)
If you don't have a picaxe programmer or programming cable you will need to get on try SPARKFUN
Step 2: Resistors and Wire link
*Solder in the wire link at S2.
Step 10: 9 Volt battery clip
*(optional) At this stage you can add some hot glue to the spot where the leads attach to PCB to stop the wires from breaking.