Hi James,
Just saw your post about the free app for your ipod touch. I posted something a minute ago about software from diabetespilot.com. It has an app for ipod touch/iphone that looks amazing.
I have copied and pasted some of the info below for you:
Records glucose measurements, insulin and other medicine, meals, exercise, blood pressure, test results, and other notes.
Tracks the carbohydrate, calories, fat, protein, fiber, sodium, cholesterol and other nutrients in the foods that you eat. Diabetes Pilot has an integrated food database with information on thousands of foods, including hundreds of fast foods.
Helps you see trends in your blood sugars, medications, diet, and other areas with various reports and graphs.
Lets you to categorize records by time of day or any other system that you'd like, further helping you to find important patterns.
Allows you to transfer your data in various ways for further analysis and communication with your health care team.
Go to the website and have a look. The only drawback I can see is that it's not free (£6.99) but looks well worth the cost.