Besides every team's official web site, here's an independent one that I use and find very useful especially when the season starts -
http://www.localsports.ca/nfl_rosters/index.html
Looking over my 49ers team, here's what their 54 player roster looks like as of now -
qb(3) - Smith, Hill, O'Sullivan
rb(6) - Gore, Foster, Clayton
fb(7) - Robinson
wr(13) - Battle, Johnson, Bruce, Hill, Lelie, Morgan (R)
te(17) - Davis, Walker, Bajema, Jennings
c(19) - Heitmann, Wallace (R)
og(22) - Baas, Snyder, Rachal (R)
ot(25) - Staley, Jennings, Sims
dt(28) - Franklin, Fields, Cohen
de(32) - Smith, Sopoaga, Balmer (R), McDonald
olb(37) - Lawson, Cain, Green, Haralson, J. Moore
ilb(42) - Willis, Spikes, Ulbrich, Thomas, Grant (R)
cb(48) - Clements, Harris, Spencer, Strickland, Hudson, Brown
ss(50) - M. Lewis, K. Lewis
fs(52) - Goldson, Smith (R)
k(53) - Nedney
p(54) - Lee
Notes -
1) J.T. O'Sullivan is on track to be the starter but there's no way in hell that he should be. As a 49ers fan, m happy with Martz and Nolan and if Sullivan is named starting QB, GM Scot McCloughan should fire both for several valid reasons which if you want to see, go to nfldraftcountdown.com and go to the 49ers team forum.
2) FB isnt a need with Martz as OC. Norris is expected to be released with Keasey expected to make it past the final cuts. However, I would much rather see Robinson as an RB/FB/HB type so Clayton can make the roster.
3) A lot of people are expecting to see Lelie get released since Morgan has outplayed him and others thus far but considering the talent and depth, I would keep all six receivers.
4) Defensively, im guessng that FS Mark Roman will get released if Goldson wins the starting job. Rookie Reggie Smith is playing cornerback but most expect him to be the future FS as do I.
5) The first name listed at each position is the starter with the second name being the co-starter or backup depending on the position.
Hope this helps.