I started 10Mi TT's this season, as a complete newbie to bikes.... first attempt was a 30.5secs, and over the course of a season, with some regular training, got that down to high 26's...
One of this winter's goals, as part of my IM programme, is to start the next season with a 24
I'm also going to try the 25 and 50 mi TTs... no idea what to expect! 
This next bit will be of absolutely no interest to the guys that are posting times I can only dream of on the other thread, but perhaps of interest to those contemplating their first TT as absolute beginners like I was back in May....The biggest three things I learnt in my first season were:
1] Pacing myself... even for a 10mi TT, you can't go off like a rat out of a drainpipe... you need to be quick from the go, but not so quick that you die on the second half
2] Climbing... being in the right state for a climb is so critical... it may feel good to be averaging 25mph when you reach the foot of the climb, but if you die going up it, your average plummets.. better be a tad slower to the climb, and then be able to get up it quickly
3] Getting the right gear for the climb is key... it may be easy to select the granny ring, and bang out the climb with a cadence of 130, but its quicker to notch it up a few, and work on power... yes it hurts, but you'll be quicker overall.
Edited: 13/09/2010 at 14:12