As per TartanJack's request I have made this a sticky. Its a list of cars that have the same bolt pattern for those that might wanna get different steelie wheels. I have left out the trucks as they will not work due to the offset and design for RWD use.

5X114.3 Cars
Acura
Integra Type R (1997-2001)    RSX (2002+)
CL (1998-2000)    Legend (1991-1995)
TL 3.2 (1996+)     
Chrysler
Caravan (1999-2003)    LHS (1995-2003)
Chrysler Sebring (1995-2003)     
Dodge
Stealth RS Turbo (1994-1996)    Stratus (2002-2003)
Talon(1990-1998)    Avenger (1995-2003)
Ford     
Ford Probe(1989-1997) Hub bore 59.6     
Honda     
Prelude (1997-2001)    Honda CRV (1997-2003)
Civic Si Hatchback (2002+)     
Infinity
Infinity I35 (2000-2003)    Infinity I30 (1996-1998)
Infinity G35 (2004+)     
Lexus
ES300 (1997-2003)    GS300 (1993-2003)
GS400 (1998-2002)    GS430 (1998-2003)
LS400 (1990-1994)    IS300 (2000+)
Mazda
929 (1988-1994)    626 (1988+)
Protégé (2002+)    Protégé 5 (2002+)
Mazda3 (2003+)    MP3 (2002+)
Mazda6 (2003+)    Mazda5 (2005+)
MX-6 (1988-1992)    RX-7 GXL GTU Turbo II (1986-1992)
Mazda RX-7 (1993-1996)     
Mitsubishi
Diamante (1991-1996)    Eclipse (1989+)
Galant (1997+)    3000GT SL (1991-2000)
Lancer Evolution (2004+)     
Nissan
Altima (2002+)    Maxima (1989-2003)
240SX SE (1995-1997)    350Z (2004+)
Toyota
MR-2 (1990-1995)    Supra (1986-1996) including Turbo
Camry Solara (1999-2003)    Camry (1992+)

Bookmarked!! Thanks for the info Jack's!

The xB's factory offest is +45. However you can run up to a +25 (depending on wheel design).

Oh and for those that don't understand offset here is a basic tutorial.

Offset is the distance that the mounting surface is located from the center of the vehical.  Zero (0) offset means its in the dead center of the wheel. Plus (+) offsent is how far towards the outside of the wheel it sits. And Minus (-) is how far towards the inside the wheel it sits.

Ok if you get a wheel with 48mm offset then then the wheel will actually sit inside the wheel well more. If you get a 42mm offset it will stick out of the wheel well more. Ever seen the photos of my rims? They are a 25mm. However you have to realize that there is negative and posative offset. You won't see negative offset on FWD, they are usually for RWD. Well you might but they will be sticking way out of the car and need some major mods to clear. Quite honestly I don't know what kinds of cars run negative and which run posative any more. So many different wheel designs an cars out there and they aren't as universal as they used to be. Even RWD cars these days don't run similar wheels anymore due to changes in suspension design and larger disc brakes on the front and rear of cars.

A 48 offset sets the wheel further into the wheel well.  So, if you do that, don't get too wide of a rim or it might not clear on the inside of the wheel well.
(That would be a bad thing.)

I am fairly new to xBs (not quite 2 months), so I don't know the clearances or what are the width/offset limits.  Thus, I can't give any advise.
48 isn't much more than 45 (3mm), so it might not be an issue.  I just don't know.

Personal opinion:
With an stock offset of +45, I would go with a lower offset (number less than 45) long before I would go with a higher one.  Many xB2 people run offsets in the 25-35 range and many between 30 and 35.
(Hey, I have read a bunch on these forums to learn more about that hunk of metal in my driveway . . . )
Therefore, between a 48 offset and a 42 offset (all else being even), I would probably get the 42 myself for a rim set (especially if it is significantly wider than the stock steelies).

The problem with this question is that its tricky. It depends on HOW the wheel is wider. Not all wheels are made even. Some are wider on both sides. Some are wider in the back, and some are wider in the front. It depends on the design.

you know that you can use certain truck rims... I have to find out the year s but i know if it is a bagged truck they have to have different offset to tuck into the fender lips... so they will work!

No.  Not by itself.
In fact, the aftermarket ones I have my eyes on are 16x7.

What is important is an offset in the 35-45 range, with the correct 5x114.3 lug pattern and correct center bore (60.1mm, as I recall) or larger, ideally in the correct size center hole.  It that all fits, you'd be fine