cure fraction model

Dear all, is there an R function to simulate random observations from a cure fraction model (random observations with long-term survivos). 
Some references how can I do this will be welcome.

Shouldn't be too hard to set up a mixture of weibull distributed event times with one component having a parameter less than "exponential" (to represent the cured fraction with survival typical of an average human population) and another with a hazard like an "exponential" or worse to represent the non-cured fraction. Watch out about how the shape parameters are defined. The survival package uses different parameterization than the rweibull definitions.

library(survival)
?survreg
?rweibull

David Winsemius
Alameda, CA, USA