Good way to keep track of advertisers etc etc ?

[jwocky]

Im curious if anyone can recommend some good software that would help in keeping track of advertisers on your forums. Somehting which would keep track of when they signed up, for how long, and for what level of advertising, etc... I was going to do it all in a spreadsheet but maybee some kind of professional billing software would be better. Anyone know of anything that you use or can recommend for doing just this? Im getting worried I will loose track of advertisers and when I should bill them, etc etc

thanks!