for the last month or so, whenever I turn on my car, my trip odomater flashes "oil" for a few minutes and then it goes away. Does anyone know what it means?

 

time for an oil and filter change I think or could mean check your oil

 

the owners manuel said it was to change the oil but, i just got the oil and the oil fliter changed and it still comes on.

 

when that happened to me, it meant that i needed to add more oil......

 

I guess they didn't reset the service light

edit: reset tool required, take it back and make them reset it

 

It's just a reminder to have the oil changed. If you take it to the dealer for service, they usually reset the indicator.
If you take it to a independent mechanic, sometimes they don't have the tool to reset it.
For the early 96 and 97 you need the VAG-COM tool to reset the indicator. For later years you can reset it using the stalks on the instrument cluster, RTFM for the instructions.