Because twins are so rare, you may not find anyone who can tell you which infant seat(s) fit side by side. Personally, I wouldn't go with the Peg Perego seat. It cannot be installed without the base, and really doesn't offer a lot of features for the money.
There's some good info on <a href="http://www.cpsafety.com/articles/infantshop.aspx" target="_blank">shoppingfor infant seats</a>on CPSafety.com.</p></span><!--StartFragment --><span class="ts1l">Doyou <em>need</em> an infant seat? Not necessarily. Some people findthey're an unnecessary expense and use a <a href="http://www.cpsafety.com/articles/ConvertibleShop.aspx" target="_blank">convertibleseat</a> from birth, while others enjoy the convenience they offer. </span><p>Pros:</p><ul> <li>Infant carriers tend to fit newborns better than convertibleseats. </li> <li>If your baby doesn't sleep well, it can be nice to carry him intothe house seat and all, rather than to risk disturbing a baby who hasfallen asleep in the car. </li> <li>An infant carrier can also help protect a baby from inclementweather. </li> <li>They can be convenient if you frequently travel with yourbaby inmore than one vehicle. You can purchase an extra base to install inyour other car, or you can just install the seat without the base.</li></ul><p>Cons:</p><ul> <li>They're bulky and heavier than carrying a baby alone. Carryingtheseat on ice, steep hils/stairs, etc. can be awkward to saythe least. </li> <li>They separate you from your baby. A huge range of studies haveshown that touch and eye contact are good for brain development.Additionally, too much time spent in car seats, cribs, strollers,swings, etc. can cause or exacerbate <a href="http://messageboards.ivillage.com/iv-ppcarseats/?msg=43554.3" target="_blank">positionalplagiocephaly</a>.</li> <li>The strollers that come with travel systems are not always thebeststroller for your situation. They tend to be lower quality than manyother strollers on the market. </li> <li>If your baby grows quickly, the seat may be outgrown within a fewmonths. This means it may not be a good value for your money.</li></ul><p>You'll have to look at your individual situation to determine if acarrier is something you want for your baby. If you decide you do wantan infant seat, here are some good ones to look at:</p><span class="ts1l"><span class="ts1l"><span class="ts1l"><span class="ts1l"><ul> <li><span class="ts1l">The <a href="http://www.britaxusa.com/products.cfm?action=ShowProduct&pro_id=D1274E39-6E8B-479C-978F16464B95C3A9" txrget="_blank"><font color="#0000ff">Britax Companion</font></a>has EPS foam, an anti-rebound bar, and side impact protection (SIP). </span><span class="ts1l"><span class="ts1l">At $175-$200</span></span><span class="ts1l">, it's pricey, but if side impact protection is importantto you,this is a seat to look at. (<span class="ts1l"><a href="http://www.car-safety.org/rearface.html" txrget="_blank"><font color="#0000ff">Rear facing seats</font></a> tend to provide very goodside impact protection. Also, a seat installed in the <a href="http://www.car-safety.org/faq.html#Q40" txrget="_blank"><font color="#0000ff">center of the back seat</font></a>is far from any potential impact points. Personally, I wouldn't be tooconcerned about added SIP for a rear facing seat installed in thecenter rear seat. For a front facing seat or booster installed inanoutboard position, I might be more concerned.)</span></span> </li> <li><span class="ts1l">The <a href="http://www.combi-intl.com/combi/8000.htm" txrget="_blank"><font color="#0000ff">Combi Tyro</font></a> also has EPS foam and is very well padded. </span><span class="ts1l"><span class="ts1l">Its $120-$145 price tag</span></span><span class="ts1l">is a bitless intimidating than the Companion. This seat would be at the top ofmy list to try out if I needed an infant seat.</span> </li> <li><span class="ts1l">The <a href="http://www.babytrend.com/carseats/latchlocarseat.htm" txrget="_blank"><font color="#0000ff">Baby Trend Latch-Loc</font></a> (aka Pegasus) and <a target="_blank" href="http://www.babytrend.com/carseats/tahoe.htm" txrget="_blank"><font color="#0000ff">Baby Trend Tahoe</font></a> haveEPS foam and rigid LATCH connectors which are extremely easy to use.The Tahoe is available only as part of the <a href="http://www.babytrend.com/travelsystems/travel.htm" txrget="_blank"><font color="#0000ff">Tahoe Travel System</font></a>.At $80, the Latch-Loc is affordable.</span> </li> <li><span class="ts1l">The <a href="http://www.gracobaby.com/products/subcategory.asp?N=41+108&act=A20" txrget="_blank"><font color="#0000ff">Graco SnugRide</font></a> isan option as well. It does not have EPS foam yet, but Graco should bereleasing a version with EPS foam in the next month or two. It has thewidestrange of covers. A few models have memory foam for comfort, which <em>may</em>also help in a crash. Models with a 5-point harness and frontharnessadjuster usually run $90-$140. Models with a rear adjuster are evenless expensive, though a bit harder to use. Also, Graco prohibitsinstalling the SnugRide with a lapbelt that is front of the bight (seatcrack), so you should check to see what kind of seatbelt you havebefore purchasing the SnugRide.</span></li></ul>Hope that helps!