Can a lich's phylactery be recreated? I know that the phylactery is his life force, but what happen's if it is destroyed while the lich has not "died" physically yet? Would it be possible to recreate a phylactery even if he put his life force in his previous one?
The latest and most official rule for 3.5 is from Libris Mortis, which states that a lich cannot create a second phylactery at all, even if the first is destroyed. This contradicts (and supersedes) an earlier (3.0) rule from the Savage Species Lich Template Class. Many thanks to @ColinD for linking those.
Note that if you do not have Libris Mortis or that particular Savage Species web enhancement in play, there is no rule on the subject at all. The lich monster entry states that the purpose of the phylactery is to store the lich’s life force in it, and then goes on to describe how it is made: with no restriction mentioned, it seems possible to create more than one, but the role of the phylactery during the ritual itself and the uniqueness of one’s own lifeforce may imply that the process cannot be repeated.
Note that resurrection and true resurrection return an undead creature to the life they once had. If nothing else, even in the case of Libris Mortis, a lich could do that and then repeat the process of becoming a lich, creating a new phylactery. Any living creature is eligible to become a lich; there is no requirement that they cannot have been a lich previously.
If Libris Mortis is not in play, this can even done to the remains of a destroyed lich, but with Libris Mortis, there is a clause that “If a lich without a phylactery is slain, the lich is forever destroyed.” Whether that only means in the automatic fashion typical for liches, or at all under any circumstances (and whether that is going to trump the rule that undead can be restored to life) are all very ambiguous questions that need to be answered by the DM.
Finally, the dry lich (Sandstorm) may have different rules, since they start with several phylacteries.
According to Libris Mortis, No
Libris Mortis p. 151 says you can only create one phylactery. If it's destroyed and you're still alive, nothing happens to you until you die, at which point you're destroyed.
A lich whose phylactery is destroyed suffers no harm, but cannot create a new one. If a lich without a phylactery is slain, the lich is forever destroyed.
According to the Lich Template Class, Yes
If the phylactery is destroyed while the lich is still active in a body, her undead life force automatically joins that body. She takes no penalties of any kind for that joining, but without a phylactery, she cannot recover if her body is subsequently destroyed. She may create a new phylactery to replace a lost one if she has the time and resources to do so.
Libris Mortis is a 3.5 source, and the template classes, while seemingly made with 3.5 in mind, are based on material from Savage Species (which is 3.0). They're also aimed at letting PCs acquire a template in the middle of a campaign, rather than just starting with it.
As Libris Mortis is the newer source, I'd go with what it says unless you happen to want to houserule it otherwise. It would certainly add some extra tension to a game if the PCs can destroy a phylactery, and now have to race to find and kill the lich before he can create a new one!
(Whatever you rule should apply the same to Dracoliches, as the Draconomicon doesn't specify either way.)