passing package and custom fields to a template?

[Snowman]

I need to pass some variables thru to a new page I am developing

 

for example i need to grab $service.server, a custom field called username2 and one called password2 and put them into a url to pass the variables thru to another page or alternatively pass the package id thru and then grab the variables from the database based on that package id being passed thru the url

 

can someone guide me on the best way to grab these variables