The 1.1.0 update is coming this week.
We don't really know when yet, because it still needs a bit of work and we also need to contact each mirror to make them update the file. So, we can't really give you a definitive release date for the moment.
When everything will be compiled/ready, I'll make a list of changed files and see if it's a good idea to make a "1.0.0 to 1.1.0 patch". But obviously, if the patch is nearly as huge as the game itself, it would be useless. The only thing I can do for the moment, is to give you the complete change log (a few supplementary translations may be included before the update).
Portal: Prelude 1.1.0
* Added: dutch translation (subtitles only)
* Added: finnish translation (subtitles only)
* Added: hungarian translation (subtitles only)
* Added: italian translation (subtitles only)
* Added: korean translation (subtitles only)
* Added: portuguese translation (subtitles only)
* Added: russian translation (subtitles only)
* Added: spanish translation (subtitles only)
* Fixed: portals not fizzled when you handed back your portalgun
* Fixed: installer problems (mostly with Windows Vista)
* Fixed: huge freezes and lags when GlaDOS is started
* Fixed: morality core going through a grate in the last level
* Added: a toggle mode to the BTS button in test chamber 19
* Fixed: camera won't fall in test chamber 15
* Fixed: ability to go inside observation rooms using an engine glitch
* Fixed: finishing test chamber 6 could lead to Mike saying you failed
* Fixed: Erik saying "euros" instead of "dollars"
* Fixed: ability to go inside the box dispensers using an engine glitch
* Fixed: advanced chambers/challenges still locked when finishing the game
* Fixed: autosaves not correctly activated
* Added: autosaves on challenge start
* Added: autosaves after long speeches
* Fixed: player could get stuck under elevators
* Fixed: challenge 15 won't record scores
* Fixed: challenge 17 won't record scores
* Fixed: box dispensers can drop more than one cube
* Fixed: typos in french subtitles
* Fixed: typos in english subtitles
* Fixed: portal fizzler in test chamber 17 gives a cube for a camera
* Fixed: missing faces resulting in visible outside of the level
* Fixed: non-solid door in test chamber 3
* Fixed: non-solid door in test chamber 4
* Fixed: cubes can get blocked in the dispensers tube
* Added: an escape path in test chamber 9
* Fixed: glass panel can be broken with a chair in the aperture laboratories
* Fixed: cube can be lost in the orbs room in test chamber 19
* Fixed: cube can be lost before the pit in test chamber 19
* Added: a cube dispenser in test chamber 14
* Added: an alternative path in test chamber 15 (for the challenges)
* Added: a delay when turrets appear in test chamber 8
* Fixed: bogus elevator in test chamber 10
* Added: a distraction in the turrets room in test chamber 11
* Fixed: radio song does not stop when the radio is destoyed
* Fixed: moving a few autosaves and areaportals to prevent the game from crashing
* Fixed: improving lipsyncing but it's still random as faceposer keeps corrupting our sounds
* Fixed: ballcatchers can be activated with any thrown object
* Fixed: scorpions' song replaced by four variations of still alive
* Fixed: door won't open in the corridor at the beginning of test chamber 18
* Added: hints at the end of test chamber 18
* Added: a disclaimer when the game starts
* Added: a ledge for the first jump in test chamber 2
* Fixed: turrets fire too quickly in test chamber 1
* Added: a ledge for the fling in test chamber 3
* Fixed: lunch bag model sounds like metal
* Added: english part to the commentary, to point out that there's subtitles
* Added: new "directional sign" textures for test chamber 19 BTS area
* Added: hints under the stairs in test chamber 19
* Added: another path to get to the BTS area in test chamber 19
* Fixed: particles and light color of disintegrators
* Fixed: particles color of "only-portals" fizzlers
* Fixed: rework a few textures for the BTS/maintenance areas to look less old
* Fixed: clean and optimize level geometry
* Added: missing challenge records for test chamber 15
* Added: missing challenge records for test chamber 18
* Added: missing challenge records for test chamber 19
* Fixed: GlaDOS force field insta-kills too randomly and too often
* Fixed: bogus NPC animations
* Removed: alternative solution for test chamber 4
* Added: space between "only-portal" fizzlers and disintegrators in test chamber 15
* Fixed: snoozing man is not snoozing
* Added: NPCs in some empty observation rooms
* Fixed: fizzler in test chamber 15 is destroying the energy orb
* Fixed: too many letal turrets in test chamber 15
* Added: hints in the 4-turrets room in test chamber 17
* Added: a glass panel to see the rotating wall in test chamber 17
* Added: missing tubes in box dispensers
* Added: crosses on wedge shaped platforms in test chamber 19
* Fixed: GlaDOS stops attacking after her second attack in the second round
* Added: restored stairs in the BTS/maintenance area in test chamber 15
* Added: clipping in most of the stairs to avoid view shaking
* Fixed: in a rare case, the cube isn't respawned in test chamber 17
* Fixed: in a rare case, the cube isn't respawned in test chamber 18
* Fixed: overlapping blocks in test chamber 19
* Fixed: at the end, the new menu doesn't show up if the console if visible