I've seen several work units upload from 3 of my systems, however when I view my profile it still shows 0 (zero) credits??? Is there a delay in crediting work units to individuals?

To get credits, your claimed credits must be compared to the claimed credits of 2 other PC's. As long there are no 2 other claimed credits for the same WU, credits cannot be granted.
There is also a deadline of reporting of 14 days for each WU.
In normal condition, credits are awarded between some 5 to 10 days, depending on the speed of processing of the 2 other PC's as well as on the time of reporting the results for it, but it can take up to 14 days at maximum in normal conditions.

To have some more explanation about credits calculation you can have a look here.

Greetings from Belgium.
Help Desk: use "Most recent answer first" sorting