日本姓氏--沢與澤

Well I don't really how to put this, but I'll try...

Essentially, 沢 is the Japanese simplified form of 澤, although both forms are being used in modern languages, esp. in print media.

More details of the two characters here:
http://linear.mv.com/cgi-bin/j-e/sjis/tty/nihongo-de/nocolor/dokanji?PP=&RR=sawa&SS=&QQ=&YY=&WW=&EE=swamp&scope=g

Both characters essentially mean the same thing:
a. swamp; marsh;
b. mountain stream; valley; dale.

AFAIK, while 沢 is being used in normal everyday usage, 澤 is being used to designate names -- place names, surnames etc.

And remember that all Japanese kanji started with traditional characters first, then slowly progressed to more simplified forms as times changed.

In some cases, people have unofficially changed ”澤”from the surnames to its simplified form for easier communication, (and possibly for the fact that many Japanese are not very proficient in writing kanji, thus opting for simplified forms whenever possible). In the entertainment business, such examples include:
a. 澤岻奈奈子 (of the MAX musical group), who changed it to ”沢詩奈々子”;
b. 澤尻繪里香, who was alleged to have already used the form ”沢尻" back in junior high school for the fact that ”澤”has too many strokes and was thus too hard to write (according to certain discussion forums, although this is still a myth and still not verified).

Additional reference for (b) can be seen here (again, not officially verified):
http://hitorigoto2006.sakura.ne.jp/2007/01/sawajiri1-71.JPG

Hope this helps.

2007-03-13 18:19:44 補充：
Addendum for surnames:(a) 澤岻 has the same pronounciation as 沢詩, read ”Takushi”;(b) Any name that apprears in a school yearbook is supposed to be in the truest form. In the case of 澤尻, the proof is here:http://www.anthony.hk/~g/image/salope48/mugshot/kShirigaruEflash0123-igusa01s.jpg

以我既睇法黎講2個既意思
"沢"="澤"
其實係日本姓氏入面係一樣意思,,冇咩分別!!
不過2個讀音同叫さわ（sawa）
但亦有時"沢"係讀ざわ(zawa),,係因為前面有另一個讀音,,所以讀音由さわ變成ざわ。
eg.沢尻エリカ　（さわ）
eg.池澤（いけざわ）