All three Mass Effect games are going to be bundled together at retail, as BioWare announced the Mass Effect Trilogy will arrive on November 6 for the PC and Xbox 360. The PlayStation 3 version currentlly has no announced date and there was no explanation given for its delay. The first Mass Effect never appeared on the PS3, just PC and 360, while the sequels were on all three platforms. However, PS3 gamers who already own Mass Effect 2 and 3 do not have to buy the collection as ME1 is set to arrive on the PlayStation Store. No release date or price was announced for that one, but I do not think it will cost more than $20.
Neither BioWare or EA made any mention if the DLC for the Mass Effect games will appear with the collection; hopefully an announcement is made soon regarding that. The Mass Effect Trilogy is priced at $60 for all three platforms.