Cooking

Tallow can be substituted in almost any recipe that calls for oil, butter, or lard and it works very well

Bread Spread

Whip your favourite herbs and spices such as garlic, onion, and celery with your tallow and use it as a replacement for butter. Do not knock this until you try it as it is really nice on grilled cheese.

Soap

Try mixing lye with the tallow to create a very good soap. Here is a good page from Miller Homemade Soap to help get you started.

Bio-diesel

Yes you can create bio-diesel from any fat including tallow. Biodiesel Magazine has a great article on using animal fats in biodiesel production and you can read it here. Do not use the advice of some of the idiots out there that equate pure unprocessed animal fats with biodiesel as this could lead to serious damage to your engine, All oil and fats must undergo the transesterification process to make it biodiesel.

I am sure there are numerous other applications for wonderful tallow and I would love to hear about them if you know of them.