[R] need help in mixed poisson regression

Dear all,  I have a mixed Poisson regression model . my function is: ## P(N=k)=[(a+2)/a ][(lambda^k)]*[((a+2/a+1)+lambda)^(-k-1)-(a+2+lambda)^(-k-1)]; lambda=a0+a1*x1+a2*x2 This is same as a Poisson-inverse gaussian or Poisson-lognormal regression.I want to estimate the parameters by fitting th

[R] poisson lognormal regression

Dear all, I want to directly write the loglike function of poisson- lognormal regression and then estimate the parameters. the response (Y)is count and I have two explanatory variable (x1:nominal) and (x2:continiuouse). which package in R can be used ?.How can input the data and write the loglik