Apple released updates for iLife '08 last week, fixing bugs in most of the applications but also significantly addressing some of iMovie's shortfalls (see "," 2007-09-07). The updates are available via Software Update or as stand-alone downloads; they all require  (7 MB download), which updates shared components.
Some of the changes in (44.6 MB download) restore features from iMovie HD 6 that didn't cross over to the new iMovie 7 (which was created from scratch). It can now create still frames from video, select multiple clips, set a custom duration for audio fades, and perform frame-level trimming. Other improvements simply make sense, such as changing the duration of still photos or transitions without going into the Preferences dialog, controlling the level of ducking (dropping the audio volume to make way for other overlapping audio), and displaying the current playhead time when Playhead Info is activated. Apple also claims performance improvements when switching between iMovie Events.
iMovie 7.1 also restores timecode to the application. Previously, footage was referred to only in increments of tenths of a second, which I suppose is more comprehensible to video editing novices and also seems to be the approach favored by tapeless camcorders that record to memory cards or internal hard disks. But the rest of the video world uses timecode, which expresses footage as minutes:seconds:frames, with each second comprising 30 frames for NTSC video or 25 frames for PAL video. A new Display Timecodes setting in Preferences activates the feature.
In terms of the other iLife '08 applications, (59.3 MB update) fixes issues with stability and moving photos between events, and adds new greeting card themes in anticipation of the holiday season.  (18.6 MB download) appears to be just a bug-fix update.  (46.1 MB download) addresses problems with third-party audio software, display issues, and the Magic GarageBand feature.  (17 MB download) addresses upgrading iWeb 1.x sites and fixes "some common publishing problems."