In the Doctor Who movie The Doctor has to transport The Master's remains. These remains then turn into a snake creature which takes over a human body.
Is this common for Galifreyans or Timelords when all of their lives are used up?
Per Wikipedia on the subject;
In the prologue, the Master (portrayed by Gordon Tipple) was executed by the Daleks as a punishment for his "evil crimes". The Master survived his execution by taking on the form of a small, snake-like entity. This entity escaped and slithered inside the Doctor's TARDIS console, forcing the vessel to crash land in San Francisco.
The novelisation of the television movie by Gary Russell posits that the modifications and alterations that the Master has made to his body over the years in attempts to extend his lifespan had allowed this continued existence, and the implication is that the "morphant" creature is actually another lifeform that the Master's consciousness possesses.
This interpretation is made explicit in the first of the Eighth Doctor Adventures novels, "The Eight Doctors" by Terrance Dicks
'How does it work?' asked the Master eagerly.
'You swallow the deathworm before you go into danger. It becomes dormant and lives inside your body. If you are killed it absorbs your essence, body and spirit. It lives on in your remains - in the ashes even, if the body is burned.
As soon as it can, it seeks a new host. It takes over the host and then it dies, but you live again in a new body!' Eyes gleaming, the Master picked up the clay pot and clasped it to him.
This was also used in the Doctor Who Magazine comic strip story "The Fallen" (DWM #273-#276), which states that the morphant was a shape-shifting animal native to Skaro.