hi siblin
just to let you know our experience
our meds were done 28apr08 the following week they were posted by courier (which we paid around £60 for - directly to the doctor that did them). we got the tracking number from the doctors surgery and followed the progress on the internet all the way to sydney - where they arrived by the end of that week.
they then need to go from sydney to the aspc eventually - which i never tried to track on the internet - dont know if you can. anyway from here we just asked through our agent if they were where they needed to be so that our application could be processed further (as when we did have the meds done our doctor had mentioned that case officers were calling up asking for people to be sent for their meds who had in fact already been - this was something to do with them being stuck in sydney when they should in fact be at the aspc) our agent confirmed they were with aspc and they were finalised by the 22may08. if you do not have an agent - and if you have applied on line - check on the diac website on the query application staus page for the word finalised next to the meds
all in all - for us anyway - everyone will be so different (as you can no doubt tell from the way they are granting visas at the minute!) about 4 weeks so you have no worries but as i said there are checks you should be able to do to trace the progress to keep your mind at peace.
hope that wasnt too long winded
good luck
sjs