[TIP] Looking for a decent issue tracking system

[Tim Hatch]

> One alternative is for the tool to let the project
> manager plan the iteration by hand but to warn him if he puts in more
> stuff that can fit in the iteration given the current team velocity.

Have you considered FogBugz?  It's not open source but I've heard it has
a feature called "Evidence-Based Scheduling" which might fit the bill
for the warning case above.

http://www.joelonsoftware.com/items/2007/10/26.html
http://www.fogcreek.com/Fogbugz/LearnMore.html?section=PredictShipDates

Tim