Basic query performance question

Hi,

I have a question about query performance. I have a pretty large query that hits a little of all my tables in the database. It uses only index scans(mostly on my foreign key and primary key indexs). I notice that the first time it is run for a particular set of parameters it takes about a second. However, if I rerun the same exact query it takes about 1/1000 of a second.

I know this is pretty basic, and I think I understand the reasons, but is it just because after the initial query, the pages are now sitting in memory still? Is there anyway to take advantage of that for my initial run of the query?

Thanks,
Morgan